Produced by Clare Friedland, Lourdes Aguiar, Elena DiFiore and Shoshanah Wolfson

[This story previously aired on July 15, 2017. It was updated on Dec. 29, 2018.]

Matt Herren still struggles to make sense of what happened the night of Oct. 12, 2012, when his close friend, Ryan Poston, was killed.

"I think about him every day," Herren said. "You don't think something like that is ever going to happen to someone you know."

"Is there something I could've done that could've prevented that? And I know a lot of people in his life had to have felt the same way," Herren told "48 Hours" correspondent Peter Van Sant.

Shayna Hubers and Ryan Poston

How did things spiral so out of control between Ryan and his girlfriend, Shayna Hubers, that she shot him to death -- insisting it was to protect herself?

"What was lost when your friend was shot and killed?" Van Sant asked Herren.

"He's the type of person that you want in your life," he replied. "Not just a friend, but a loving son, a protective, adoring older brother."

"He had three younger sisters that he absolutely adored," Herren continued.

Ryan's family was close-knit even though his parents divorced when he was little. He was extremely close to his father, Jay Poston. And when his mother remarried, to Peter Carter, Ryan thought of him as a second father.

Ryan Poston, second from left, with his parents. From left, Jay Poston, Lisa Carter and Peter Carter.

"He had two men who loved him like a son," Herren explained. "He wanted to express how big of a role both of those men played in his life ... so he had his middle name legally changed to Carter. He was very proud of that."

"What did he want to do, what did you see him doing in the years ahead?" Van Sant asked.

"You know, I used to joke that I would run his first political campaign for him for free," Herren said, smiling.

Sarah Robinson, who grew up with Shayna Hubers in Lexington, Kentucky, says Shayna's future seemed promising as well.

"And how smart was she?" Van Sant asked.

"I thought she was, close to genius, in myopinion. I mean, she always was in AP classes, always getting A's in everything," Robinson replied.

Shayna Hubers

Shayna received countless awards for academic excellence and leadership.

"She liked to succeed at anything and everything that she did," said Robinson.

And that included music and drama.

"Was she a good actress?" Van Sant asked Robinson.

"She thought she was," she replied.

Robinson says back in high school, Shayna also had a real flair for the dramatic when it came to boys.

"If a guy, like, broke up with her or something or if a guy just said they weren't interested in her she would take it pretty hard," she explained. " ... crying and maybe a little screaming ... she didn't really like to let things go."

It was a side of Shayna that Ryan would come to know all too well. Shayna went to school in Lexington, more than 80 miles away from Ryan's condo in Highland Heights. The two probably never would have met if it weren't for Facebook. He spotted provocative photos of her, and they started dating in the spring of 2011. He was 28 and a lawyer; she was 19 and a college student.

Asked if Shayna was happy, Robinson told Van Sant, "Um, yeah, she seemed to be happy. I mean, she never said that there was anything wrong in the relationship."

But according to Ryan's friend, Allie Wagner, there was plenty wrong right from the start.

"How did Shayna react when she first met you?" Van Sant asked.

"She was so cold. You could just immediately tell that ... she was just obsessed with him," Wagner replied. "I think she had a goal, in the beginning, to make him settle down with her. And when she wasn't becoming successful, that became a problem."

"He was very busy with work ... he wasn't really looking for anyone," Herren said. "He had tried to end things a few times."

But Ryan was having a tough time getting Shayna to let go. Shayna admitted in a text to a friend: "He says he's only with me bc I make him feel so awful about it when I cry."

"He didn't want to hurt her feelings. Unfortunately, she just refused to take no for an answer," said Herren.

And so the two were on-again and off-again for 18 months.

"She would come by his place when she was in town," Herren told Van Sant of the unannounced visits.

As Shayna became more possessive, Ryan's exasperation and concern grew. In a text to his cousin he wrote: "This is getting to be restraining order level crazy ... She's shown up at my condo like 3 times and refuses to leave each time."

He also complained about Shayna's obsessive behavior in a Facebook message to Wagner:

"'Literally probably the craziest f-king person I have ever met. She almost scares me,'" Wagner read aloud.

"I wish I had said, 'If she scares you or if she's crazy, just walk away,'" said Wagner.

Instead, he kept taking her back.

"I think he was playing mind games with her," said Ryan's neighbor, Nikki Carnes.

Carnes claims there's another side to this turbulent relationship. Shayna complained to her that Ryan was emotionally abusive.

"She would always tell me that he would say she needed a boob job or a face lift and that she was fat; she needed to lose some weight," she said.

"Why wouldn't she have left?" Van Sant asked.

"I guess because she was young and she always told me she loved him," Carnes replied. "She picked up his laundry, she did his laundry, she took his dog out, she went and bought him food. She did everything for him."

"Could there have been a Ryan that you didn't know? Someone that had a dark side?" Van Sant asked Wagner.

"No," she replied. "In the 10 years I knew him, never once raised his voice ... he's always been the same; super nerdy, super sweet."

Ryan hoped Shayna had finally gotten the message when he told her he wasn't going to see her that weekend of Oct. 12, 2012. What he didn't tell her was that he had a date with a world class beauty, Audrey Bolte, Miss Ohio USA 2012, whom he also met on Facebook. But he did tell Wagner, a former beauty pageant contestant herself,who knew Bolte.

"She's very beautiful ... very personable and all that kinda stuff, so Ryan was a perfect match for her," Wagner said. "He was really excited to go."

Ryan and Miss Ohio were supposed to meet at a bar that Friday night. But Shayna showed up at his condo, and Ryan never made it.

Shayna Hubers to 911: He beat me and tried to carry me out of the house and I came back in to get my things and he was right in front of me and he reached down and grabbed the gun and I grabbed it out of his hand and pulled the trigger. 911 operator: And how long ago did you shoot him? Shayna Hubers: I don't know, 15 ... 10, 15 minutes ... not even that long. 911 operator: 10 or 15 minutes ago? Shayna Hubers: Yeah.

"Someone shooting someone and then waiting 15 minutes to call. That in itself was bizarre," said Lt. Dave Fornash, who, along with his partner, was the first to arrive on the scene.

911 operator: I want you to go to your front door. I want you to open it up; walk outside the door with your hands in front of you. Shayna Hubers: OK, I will.

"We instructed her to get on the ground," Lt. Fornash explained. "As I entered the apartment I saw Ryan Poston's body on the floor in the dining room, behind the dining room table."

Police escorted Shayna to the station knowing she had shot Ryan to death.

But was itto save her life? Or had she entered Ryan's condo with a plan to take his?

BIZARRE BEHAVIOR

Even seasoned investigators could never have imagined what would unfold in the hours after Shayna Hubers killed Ryan Poston.

From the moment Lt. Fornash brought her into that interrogation room, Shayna's behavior was bizarre.

"It was crazy ... you just wouldn't believe it," said Lt. Fornash.

[Police video] Lt.Fornash: Do you smoke? Shayna Hubers: I will if I can.

"As he started to leave she started making noise as if she was crying or trying to cry or wailing," said Highland Heights Police Chief Bill Birkenhauer.

[Police video] Lt. Fornash: I'll be with you in just a second. You're fine.

"...and as soon as he walked outta the room she stopped immediately," Birkenhauer pointed out.

Chief Birkenhauer was immediately suspicious.

"Like a light switch," Van Sant noted of Hubers' behavior.

"Exactly," said Birkenhauer.

"And what are you thinking when you see that?" Van Sant asked.

"Right off the bat, I'm thinking that she's, you know, pretending," Birkenhauer replied. "She wasn't crying. No tears came out of her eyes."

Shayna was then read her rights.

[Police video] Shayna Hubers: I do want an attorney. Lt. Fornash: OK. So I can't ask you any questions at all.

And although she asked to see a lawyer, she found it impossible to remain silent:

[Police video] Shayna Hubers: I was so out of it... [Police video] Shayna Hubers: I was like, "It's in self-defense, but I killed him and can you come to the scene?" [Police video] Shayna Hubers: I was raised really, really Christian and murder is a sin.

"It just seemed like she was constantly just babbling," said Fornash.

[Police video] Shayna Hubers:You have really pretty teeth. Did you have orthodontia?

"She talked so much that, the officers were wanting to leave the room," said Fornash.

[Police video] Shayna Hubers: If I had to go to jail, can you shower there? Or do you just get really dirty?

"They were switching off so they wouldn't get burnt out," Fornash explained.

[Police video] Shayna Hubers: What are they gonna do with me? Male cop: I don't know. They just told me to come in here and sit with you.

For almost three hours, Shayna told anyone who would listen about an alleged history of abuse by Ryan...

[Police video] Shayna Hubers: He's pulled guns on me as jokes before.

...leading up to a fight in which, she says, she feared for her life.

[Police video] Shayna Hubers: And I shot him in self-defense because he's done stuff before where I've hit my head on a headboard... Lt. Fornash: OK. Shayna Hubers: ...and could've died!

But the more she talked, the more her words would come back to haunt her.

"This story never stayed the same," said Birkenhauer.

Beginning with exactly how Ryan's gun ended up in her hands:

[Police video] Shayna Hubers: And he was screaming at me, telling me I was a f---ing hillbilly; that he f---ing hates me.

By all accounts, Ryan -- who owned several guns and was licensed to carry -- had a habit of placing his handgun on the dining room table after coming home from work.

[Police video] Shayna Hubers: And I just picked up the gun. And in the middle of him doin' somethin' with his arm or saying somethin' crazy, I shot him.

This time she told police that she picked up the gun off the table while Ryan was yelling at her. But remember, Shayna had told the 911 operator a different story about wrestling the gun away from him:

[911 call] Shayna Hubers: ...and he reached down and grabbed the gun and I grabbed it out of his hand and pulled the trigger.

But Shayna didn't stop at one bullet. As she described the final moments of Ryan's life, the details were beyond disturbing:

[Police video] Shayna Hubers: And he was laying with his face on the table, like twitching. And so I knew he was gonna die. [Police video] Shayna Hubers: And I walked around the table [cries]. And I think that's when I shot him... in the head. I shot him probably six times, shot him in the head. He fell onto the ground. He was, like, laying like this [she gets down on the floor]. His glasses were still on. He was twitching some more. I shot him a couple of more times just to make sure he was dead 'cause I didn't wanna watch him die.

"She didn't say that she was worried about him sufferin', she said that she couldn't stand to see that, is why she finished him off," said Birkenhauer.

"If someone's wounded on the ground, someone that you love, wouldn't you ... attempt to resuscitate, to save, rather than shoot him?" Van Sant asked.

"Or call 911," the chief replied.

Instead, Shayna admitted she waited at least 10 minutes to call for help.

Prosecutor Michelle Snodgrass says Ryan was helpless.

"He laid there helpless and she walked over and shot him again and again and again. That's not self - defense," she explained.

[Police video] Shayna Hubers: I knew he was gonna die or have a completely deformed face. He's very vain ... and wants to get a nose job; just that kinda person and I shot him right here ... I gave him his nose job he wanted.

"My jaw hit the floor. I said to myself, 'did she really say that?'" said Chief Birkenhauer.

And Shayna had plenty more to say as she twirled around the room:

[Police video] Shayna Hubers: I did it! Yes, I did it!

Even when Shayna wasn't speaking, her actions spoke volumes to the investigators who were watching from the other room. Not only did she dance and twirl, she even sang "Amazing Grace."

"How do you respond to what we're looking at here -- is a woman in shock?" Van Sant asked Snodgrass as they watched the police video.

"Someone who is in shock does not pirouette," she replied. "Within hours of putting six bullets into Ryan Poston and watching him die, she danced and sang."

[Police video] Lt. Fornash: Here's what's gonna happen right now Shayna, OK, with everything that we have ... um ... we're gonna ... I'm gonna ch... I'm gonna have to charge you with murder."

Shayna Hubers was arrested for murder:

[Police video] Shayna Hubers: What degree? Lt. Fornash: Murder.There's no degree.

Ryan had been shot six times.

"Pretty much every side of his body, he'd been shot at," said Birkenhauer.

"Doesn't that fit someone who fears for her life at that moment, that she's being attacked, that she has to use excessive force to put down the threat?" Van Sant asked.

"It more likely indicates somebody who's very angry," the police chief replied.

The investigation was far from over. Shayna claims Ryan had a dangerous temper -- and she can prove it.

TEXTS AND TEMPERS

Ryan Poston's friend, mentor and chess rival, attorney Ken Hawley, relished their competitive matches that would sometimes stretch out over days.

"The chess board today is how it was on the day Ryan died, mid-game with the pieces unchanged from where it was then," Hawley said. "And I haven't been able to let it go, really."

But now, that chess board sits in his office, frozen in place, a metaphor for a life cut short.

"When somebody is erased at an early age like that, what has the world lost by not having the benefit of what they would've come to be?" said Hawley.

Hawley and his legal assistant, Lori Zimmerman, had offices in the same building as Ryan. They witnessed Shayna's obsessive behavior - and the toll it took on him.

"If she couldn't get him on his cell phone, she'd call the receptionist and ask for him. Or she'd show up here. I mean, it was relentless," said Zimmerman.

"And she would text him 50 to 100 times a day," Hawley said. "She would just wear him down and exhaust him to the point where he would say, 'OK, Shayna.' ...He kept doing the easy thing, which was staying with her."

When Ryan left work for the last time the evening of Oct. 12, 2012, he told Zimmerman about his big date.

"He said, with a big smile on his face, 'I have a date with Miss Ohio tonight,'" she said.

His news gave Zimmerman an uneasy feeling ... about Shayna.

"And I said, 'I'm very nervous about what you're doing tonight because who knows what Shayna will do. You need to get her gone. I need you to call the police. I need you to call a locksmith. I need you to make it very final,'" said Zimmerman.

"And that was when he said, 'Hey Lori, I've got this. Don't you worry about me,'" she continued.

Hours later, Ryan was dead.

"I knew she was a stalker," Hawley said. "I thought she was perfectly capable of causing a scene. But murder?"

"What do you think happened the night he died?" Van Sant asked Ryan's friend, Allie Wagner.

"I think that she went over there, tried to ... talk him out of breaking up with her, she replied."And I think he just stood his ground for the first time. I think he just said no, like, this isn't working. ...I think she picked up the gun and shot him."

"In her mind, this was a failure of sorts. And Shayna didn't fail," Snodgrass said. "Shayna Hubers is someone who is used to getting her way."

"The movie 'Fatal Attraction' comes to mind," Chief Birkenhauer said. "He was trying to break up with her. ...I think that Shayna was not gonna be broken up with."

Birkenhauer says the proof is in an astonishing trove of texts and emails investigators discovered -- in numbers unlike anything they'd ever seen.

"Hundreds of thousands of messages," Snodgrass said. "And most of the messages were from Shayna. For every one message Ryan sent, she probably sent 50. She couldn't stop herself."

The messages offered a look inside this tortured relationship.

Back in February 2012, eight months before Ryan's death, he wrote Shayna: "...you can tell people you broke up with me." Part of her reply: "I love you dearly. Far more than you deserve."

In March, Ryan pleaded: "Shayna, STOP texting me." And in April, he texted: "I NO LONGER HAVE THE PATIENCE TO DEAL WITH YOU."

"Now, Ryan's a bright guy; he's a lawyer. Why didn't he get a restraining order?" Van Sant asked Snodgrass.

"Well, under the law in Kentucky, he didn't qualify for a restraining order," she explained. "...the law in Kentucky basically required the two to have been living together or to have been married."

Instead, Ryan tried to take matters into his own hands.Another text in April - this time from Ryan to his cousin: "She came to my place on Sunday morning and I literally had to pick her up and THROW her into the hall."

Still, Ryan just couldn't close the door on their relationship. The two were back together that summer, but things soured again in late August.

"And Ryan texts Shayna: 'I'm turning off the phone and padlocking the door,'" Van Sant noted to Birkenhauer. "And then she keeps texting. There are at least 100 messages until finally some nine hours later, under this barrage, Ryan says: 'I'm not reading any of these. Stop.' What does that tell you about Shayna's behavior?"

"Well, this message goes back to, she's obsessed with Ryan Poston," he replied.

Shayna once again showed up at his door. She had her own key.

"Ryan had to leave his own condo and leave Shayna in there and go spend the night with his father, because she would not leave and she continued arguing with him," Birkenhauer continued.

While the prosecution insists Ryan was the one being stalked and living in fear, Shayna told police that at times, she was also afraid of him:

[Police video] Shayna Hubers: He keeps loaded guns in the house. Had picked up a gun, pointed it at my face as a joke. "What would you do if I..." [positioning her hand as if it were a gun]

"A lot of information is going to come out about this relationship and about what happened that night," defense attorney Jon Paul Rion said. "This was not a case of anything but self-defense. This is a case where Shayna was acting to save her own dignity and her own safety."

The defense team claims there are plenty of Facebook messages Ryan sent his friends that show he was a young man consumed by anger. He'd had a falling out with his ex-law partner, who was suing him.

"August 16, 2012, less than two months before he was shot and killed, he says: 'And I wanna rig explosives to everything I see,'" Van Sant read to Snodgrass.

"Well, I don't think anybody's denying that Ryan wasn't going through an emotional time," the prosecutor replied. "He was upset about being sued by his former law partner. ...His rage was never in any of these messages, directed at Shayna Hubers, not one."

"October 4, 2012. Ryan writes this: 'There's nothing I want more than to just scorch the f-ing earth and leave this entire city in a pile of burnt rubble,'" Van Sant read. "...he's fantasizing about doing a violent act. And just day later, according to Shayna, he attacks her."

"But that wasn't a violent act directed to any person, you have to put it in context. He does not say he wants to hurt a person," Snodgrass explained.

"Pressure's building up ... He's got a girlfriend that won't let go," Van Sant pointed out. "He finally snaps. Why shouldn't we believe that?"

"There's no evidence at the crime scene to indicate that Ryan Poston went after Shayna Hubers," Birkenhauer said. "Nothing was knocked over."

"No signs of a struggle?" Van Sant asked Snodgrass.

"None," she replied.

"Are you buying this notion of self-defense at all?" Van Sant asked.

"Not one bit. Not one bit," said Snodgrass.

Photos of Shayna, taken after her arrest, show some light bruising. But police still insist there's no evidence of a life-or-death struggle. Now, the young woman suspected of cold-blooded murder heads to court to ask a judge to let her out of jail.

"A SENSELESS ACT"

"This case was always, to me, about a senseless act, senseless. Could never quite make sense of what happened on October 12th. I could never make sense of why Ryan Poston's life was ended," said prosecutor Michelle Snodgrass.

Why couldn't Shayna Hubers, a brilliant and beautiful grad student, simply walk away from her troubled relationship with Ryan Poston?

"I think it's really sad. It's kind of heartbreaking," said Shayna's childhood friend, Sarah Robinson.

Shayna Hubers' booking photo

Robinson barely recognizes the sweet, kind-hearted girl she once knew.

"I saw her mug shot. That was the first thing that I saw that really made me take a step back and just be like, 'Oh, my God," she said.

"What did it look like?" Van Sant asked.

"It looked like someone who was angry and like, someone who had just been through hell," Robinson replied.

It is June 10, 2014, almost two years since Ryan's death. Shayna has remained in jail the entire time. She has hired a new defense team led by David Mejia. At a bail hearing, they are joined by Shayna's mother, Sharon Hubers.

Sharon Hubers, a retired schoolteacher, is proud of her child's academic success.

"She graduated cum laude in three years at the University of Kentucky," she told Van Sant. "Shayna was ... pursuing a Master's degree in school guidance counseling at the time of this tragedy."

"And what do you want people to know after reading that," Van Sant asked. "What do you want them to know in relation to this case?"

"Shayna Hubers is not a child, a girl, a person that would murder someone; that would wake up and say, 'OK, I'm going to shoot somebody,'" Sharon Hubers replied.

"And I want the world to know who Shayna is. And I want them to hear it from her mother," she tearfully continued.

Through Sharon Hubers' testimony, we also learn more about the 24 hours leading up to Ryan's death.

On Thursday, Oct. 11, 2012 - the night before Ryan died-- the vice-presidential candidates were slugging it out in a televised debate. Ryan brought Shayna over to his mother and stepfather's place to watch it, and then she slept over at his condo.

"If he wants to break up with her, talk about mixed signals. Why is she staying the night at his place?" Van Sant asked Snodgrass.

"That is a question that I think a lot of people want an answer to," she replied. "I don't know if it was part of Ryan's attempt to let her down easy. I just don't know."

Ryan had already said he didn't want to see her that weekend. Perhaps that's why a distraught Shayna called her mother from Ryan's shortly after 3 a.m.

"Was she emotional? Upset?" Van Sant asked Sharon Hubers.

"Yes, she wanted mama," she replied. "I knew something was wrong."

Sharon Hubers says she met up with her daughter at Ryan's place around 5:30 that morning.

"When he woke up he saw that Shayna Hubers' mom was inside his condo," said Snodgrass.

"Shayna's mom was inside his condo?" Van Sant asked.

"Absolutely," Snodgrass replied.

"Had come in on her own?"

"In the middle of the night had driven from Lexington to sit with her daughter," said Snodgrass.

"She wanted to lay on the couch and put her feet in my lap. And she did," said Sharon Hubers.

Asked what Shayna's relationship with her mother was like, Robinson told Van Sant, "I think she was very close to her mom. I think her mom, for a good portion of her life, could've very well been her best friend."

"That child has been a blessing to me. She's my whole life," Sharon Hubers told Van Sant in tears.

Sharon Hubers would like her daughter to be released to her custody. But prosecutor Michelle Snodgrass believes Shayna is a flight risk because of what she told police:

[Police video] Shayna Hubers: A part of me wanted to get my keys, and get in my car, and leave. Because I knew my word against his and he's dead. You know, how is anyone else to know that it's self-defense, you know?

To get bail, Shayna needs to convince the judge that she's not a flight risk, and, despite shooting Ryan, not a threat to society. On the stand, she paints a picture of herself as a model girlfriend.

"Ryan was going through a lot," she said in court. "And he needed moral support. And I was always good to him."

But she also suggests she had a reason to fear him - claiming Ryan was obsessed with guns.

"Wherever you were in the house, you were always at an arm's length from a gun or a weapon of some sort," Shayna said on the stand.

"And that concerned you," Van Sant noted to Sharon Hubers.

"Oh, yes. I mean, just laying everywhere. He'd pick one up and shoot a book on a shelf or something. And did that with Shayna in the condo on numerous occasions," she said.

"Is it true that Ryan on at least one occasion did target practice inside his own condo?" Van Sant asked Snodgrass.

"We don't know if he did target practice inside his own condo. We do know that there was a book that had, you know, wood on it and some holes," she replied.

"Bullet holes?" Van Sant asked.

"Yes," said Snodgrass.

But Ryan's friend, Matt Herren, insists he was a responsible gun owner.

"He was always careful in his handling of firearms," he said. "It was never something that I worried about."

But Shayna insists she was worried enough to shoot Ryan in self-defense. And she thought that when she explained it to police that night, they would release her.

"I believed in my innocence. And I wanted to see my mother and go home," she told the court.

Now, the witness stand is about to turn into the hot seat.

SHAYNA TAKES THE STAND

Ryan Poston's volatile relationship with Shayna Hubers had become a house of mirrors--nothing was as it appeared. His friend, Lori Zimmerman, says that while the couple appeared to have reconciled in the weeks before his death, their romance was rocky.

"He wasn't happy about dating Shayna Hubers again," Zimmerman explained. "From the very start, he was working to not date Shayna Hubers again."

Ryan's neighbor, Nikki Carnes, says from what she witnessed in the months leading up to Ryan's death, the relationship was toxic.

"I was awoken out of my sleep by some screaming and yelling outside and they were arguing ... this is something that happened quite often," she said.

"Was this a nasty argument?" Van Sant asked.

"Yeah," Carnes replied.

"Everybody has a breaking point. Had Ryan reached his?" Van Sant asked prosecutor Michelle Snodgrass.

"I think Shayna reached hers," she replied.

Snodgrass believes rejection and rage sent Shayna over the edge. The prosecutor confronts her about Ryan's repeated attempts to break up with her:

Prosecutor Snodgrass: Did he invite you over? Shayna Hubers: Which night? Prosecutor Snodgrass: Well, let's say the night you put six bullets in him, how about that night? Did he invite you over that night?

"They'd broken up time and time again and gotten back together. Why did she get violent this time?" Van Sant asked Birkenhauer.

"That's a good question," he replied. "I think that she believed it was over for good, and she wasn't gonna have that."

The fireworks continue at the bail hearing over Shayna's different accounts of how Ryan's gun ended up in her hands:

Prosecutor Snodgrass: You told 911 that you had to grab the gun out of Mr. Poston's hands? Is that correct? Shayna Hubers: I did say that. Prosecutor Snodgrass: But you told the police something different, didn't you? [Police video] Shayna Hubers: It was a handgun that I used. The gun was this big. I picked it up off the table. I did have to release the safety. I did. I remember it now; I can see it in my mind."

"This is a Sig Sauer P238 .380 caliber semiautomatic handgun. This is the weapon that was used in the shooting of Ryan Poston," Chief Birkenhauer demonstrated in a gun lab. "She released the safety, pointed the gun at Ryan Poston, and shot him in the right side of the head."

Birkenhauer believes Shayna's admission that she released the safety on the gun is evidence of premeditation.

"I believe that as soon as she released the safety, she made the decision that she was gonna kill him," he told Van Sant. "It is a sign, in my opinion, that she had time to think about it."

"Show me how she released the safety," Van Sant asked.

"The safety, which right there, you can't pull the trigger," Birkenhauer demonstrated. "In order to make this gun operate and full magazine, a bullet in the chamber, you have to release the safety [click]. Now the gun's ready to go and then you just pull the trigger."

"It is an extra step that you have to think about," the chief added.

The gun itself also contained critical forensic evidence: a trace of Ryan's blood.

"And what did that tell you?" Van Sant asked the police chief.

"One or more of the shots were so close to the body when the trigger was pulled and the bullet went in, the blood came out and it landed on the gun," he replied.

Meaning, Birkenhauer believes, that Shayna moved closer to Ryan for the final kill shots.

"There was never a time after the first shot that he was on his feet," he said.

But Shayna now insists it was Ryan who was moving towards her, despite what she told police after Ryan's death:

Shayna Hubers: He was still moving. He was still coming towards me.

Ryan's downstairs neighbors, Vernon and Doris West, heard gunshots that night -- but no fight.

"First two shots we thought were firecrackers. And then there was four more. And then we knew it was gunshots," said Doris West.

"And what was the sequence of the shots?" Van Sant asked.

"Bang, bang. Bang, bang, bang, bang," she replied.

"Did either of you hear any arguing in that condo above you? Did you hear any shouting?" Van Sant asked the couple.

"Never," said Doris West.

"Never did, never did," added Vernon West.

"If there had been a fight going on up there, physical struggle between the two of them, Shayna being thrown across the floor, would you have heard it?"

"Yes," Doris West replied.

"I believe I would," said Vernon West.

The prosecutor insists that even if Shayna initially thought Ryan was a danger to her, she didn't need to keep shooting him.

"She had the door behind her with no obstructions. Why didn't she just go?" said Snodgrass.

The defense maintains that Kentucky's so-called "stand your ground" law says "a person does not have a duty to retreat prior to the use of deadly physical force." But the prosecutor believes Shayna's decision to keep shooting proves a murderous intent.

"She knew that Ryan Poston had somewhere else that he had to be and someone else that he was meeting, and she wasn't gonna let that happen," said Snodgrass.

In his questioning of Shayna, defense attorney David Mejia turns the table on the prosecution, driving home Shayna's contention that she had to use deadly force to save herself:

Defense attorney David Mejia: Now what did you believe would happen if he got up after having been shot twice? Shayna Hubers: He would shoot me; he would hurt me.

"As you well know, Shayna has been portrayed as strangely obsessive, a liar, a murderer," Van Sant noted to Sharon Hubers.

"It's been horrible. She grew up in the church," she said. "She's not a murderer."

"And the word evil has been used to describe your daughter," said Van Sant.

"She's far from evil," Sharon Hubers said. "Shayna has a heart of gold. She's like her mommy. ...a loving spirit. That's what I want the world to know."

In the end, Judge Fred Stine sets bail at $1.5 million -- too much for Shayna's parents to afford. Now, as the case heads to trial, how will the defense team overcome the one witness who could destroy any claims of self-defense? That witness -- the twirling, singing, loquacious Shayna Hubers.

[Police video] Shayna Hubers: If you go to jail, are you allowed to keep your phone?

PART 2: SELF-DEFENSE OR MURDER?

In April 2015, two-and-a-half years after Shayna Hubers gunned down her on-again, off-again boyfriend Ryan Poston, her trial is set to begin. Central to both the prosecution and the defense will be what Shayna told police.

[Police video] Shayna Hubers: And I just picked up the gun and in the middle of him doing something with his arm or saying something crazy, I shot him.

Shayna claims she shot Ryan in self-defense during a heated confrontation at his condo.

"Shayna says this is a case of self-defense. What do you say?" "48 Hours" correspondent Peter Van Sant asked prosecutor Michelle Snodgrass.

"It's a case of murder, plain and simple. Sometimes it can be that simple," she replied.

Ryan Poston and Shayna Hubers

Prosecutor Snodgrass contends that the only person whose life was in danger on Oct. 12, 2012, was Ryan Poston.

[Police video] Shayna Hubers: I think in the midst of that my love turned to hate.

"'My love turned to hate.' I think at that point in time we knew what Shayna Hubers was thinking. And it certainly wasn't that she needed to act out of fear. She acted out of hate," said Snodgrass.

Prosecutors say trouble had been brewing long before that tragic day. Ryan's cousin, Carissa Carlisle -- who was also Shayna's friend -- testified about the tumultuous relationship:

Carissa Carlisle: I believe that Shayna wanted more from the relationship than he wanted or was willing to give.

But Carlisle says Shayna would not get the message:

Carissa Carlisle [reading aloud from a list of texts]: He said to me, "This is getting to be restraining order level crazy. I'm not kidding ... You need to talk to her. ...She needs help, and I say that without exaggeration. She just really needs help."

"What did you learn about Shayna's personality?" Van Sant asked Highland Heights, Kentucky, Police Chief Bill Birkenhauer.

"The word "obsessive" is-- is a good word for her," he replied.

An obsession that Birkenhauer says can be seen in the thousands of text messages Shayna sent Ryan.

"And we know from text messages back and forth that when Ryan would end it sometimes, Shayna would just show back up and not leave," he explained.

"Refuse to leave?" Van Sant asked.

"Yes, refuse to leave," the chief replied.

By the fall of 2012, investigators believe Shayna was nearing a breaking point. Eleven days before the shooting, Shayna sent a friend an ominous text:

Chief Birkenhauer [reading the text aloud]: "Ryan doesn't love or care....He's an evil person." Prosecutor Snodgrass: And what does she say to her friend right after she calls Ryan Poston an evil person? Chief Birkenhauer: She says when she "goes to a shooting range with Ryan tonight she wants to turn around shoot and kill him and play like it's an accident."

Shayna Hubers

Shayna texted similar disturbing comments to another friend and sent a gun-toting picture.

"I think that her obsession with Ryan absolutely took a turn around this time," Snodgrass told Van Sant. "She was already making a plan to make sure Ryan did not leave her."

On Oct. 12, 2012, Ryan left work and headed home. The State believes Shayna confronted him at his condo because Ryan had told her he didn't want to see her that weekend. Although investigators don't doubt an argument took place, they saw no evidence of the violent struggle Shayna had described.

[Police video] Shayna Hubers: He was throwing me around the room, like picking me up and like had my face and stuff...

Shayna claimed Ryan had also thrown her against a bookshelf.

Shayna claimed that Ryan threw her across the room and into the bookshelf. Investigators say there were no signs of a violent fight. Of particular significance to investigators are the bullets lined on the bookshelf that are still standing upright. Highland Heights Police Dept.

"As you can see, this bookcase is covered with items that would have shifted," Snodgrass showed Van Sant. "A number of pipes along that shelf, some bullets on this shelf-- and if you look at this photograph that shows a little bit of a closer angle, none of them are disturbed."

But what really made investigators skeptical about Shayna's story was her claim that at one point during their clash, Ryan had locked himself in his bedroom.

"If someone is assaulting you, why are they the one to escape?" Snodgrass noted.

Prosecutor Snodgrass: So what was Miss Hubers Googling how to do? Chief Birkenhauer: First Googled how to unlock a house door with a bobby pin. That was a Google search.

"She found a way to unlock his bedroom door and get in there," said Snodgrass.

By now, the argument had moved into the dining room with Ryan on one side of the table and Shayna standing on the other side. Ryan's loaded handgun was on the table.

[Police video] Shayna Hubers: And he was screaming at me, telling me I was a f---ing hillbilly; that he f---ing hates me.

The jury would hear Shayna's own account of the shooting.

[Police video] Shayna Hubers: And he had his hand on the table and he wasn't completely standing up---he was like this, he was sitting ---he was ... when I shot him ---and he went like this literally," [sits and hits head on table]. That's when I knew he was dead or close to it -- and twitching.

Despite Shayna's description that Ryan was nearly dead after the first shot, she went on to shoot him five more times. But the defense maintains Ryan was still a threat.

"He was moving when these shots were fired," defense attorney David Mejia told the court.

The prosecution doesn't buy it, and they say they have the science to prove it.

Forensic expert Howard Ryan testifies that Shayna's first shot was to Ryan Poston's head -- a significant fact because there was no blood on the front of his shirt.

Howard Ryan | Forensics expert: If he was in an upright position, the gravity would have brought it down, straight down the shirt through the bottom of the shirt to the pants.

Using the very blood-stained table taken from Ryan Poston's condo, Snodgrass demonstrates why investigators are convinced that Ryan was sitting and never stood up after the first shot.

"When she shoots him in the forehead, at that point in time, his head goes down on the table. As you can see that exposes the upper portion of his right back which we believe was the second shot. At the same time, as well, his right arm is dangling which again opens up the area where the third shot occurred which was right under his arm," Snodgrass demonstrated for Van Sant.

"And where's his body going?" Van Sant asked.

"And then at that point in time, Ryan starts to fall out of the chair," Snodgrass explained. "He ultimately ends up laying on the floor."

While Ryan was down on the floor, Snodgrass says Shayna then finished him off.

"He was helpless," the prosecutor said. "That's not self-defense."

To bolster their case, the prosecution calls three jailhouse informants who befriended Shayna behind bars.

The women, convicted felons who have a history of drug abuse and multiple arrests, say they came forward because Shayna had shown no remorse. They deny receiving any special treatment for their testimony:

Prosecutor Snodgrass: What did she say had really happened? Holly Nivens: What really happened? That she was the aggressor in the fight. Prosecutor Snodgrass: Did she talk to you at all about what she thought was going to happen when she came to court? Cecily Miller: She said she was gonna plead insanity, but then she said that she's too smart because she has an IQ of Einstein ... so she was gonna plead the wife battered syndrome and say that he beat her. Prosecutor Snodgrass: Did she express any emotion when she would talk about this? Donna Dooley: I'd see no remorse. She played more the victim role.

According to this last informant, Shayna knew that Ryan had a date with former Miss Ohio USA Audrey Bolte.

Audrey Bolte: We were going to meet at a local bar and grab a few drinks and play pool and just have a low-key fun time.

"And how did Shayna react to that news that he was about to go out with a beauty queen?" Van Sant asked Snodgrass.

"That was her breaking point. She picked up a gun and stopped him," she replied.

Shayna Hubers strongly denies she knew about the planned date. As the State's case winds down, Ryan's parents tell the jury of their profound loss:

Jay Poston: Ryan was my world. When people would ask me about my child I wouldn't say he was beautiful, even though he was, or was brilliant, even though he was. I would say my son has a kind heart. Lisa Carter: I can tell you one thing, I was the luckiest woman on earth for 30 years. Prosecutor Snodgrass: Tell me about the last time you saw not only her, but your son. Lisa Carter: It was the night before she murdered him; she came to my home and ate at my table.

"I think that Shayna Hubers is a personality unlike any that I've seen in all the years that I've been prosecuting,' Snodgrass told Van Sant. "It's not a pretty picture."

But the defense is about to turn the tables on the prosecution.

KILL OR BE KILLED?

"That child has been a blessing to me," Sharon Hubers said in tears. "She's my whole life. My life didn't happen until Shayna was born."

Retired school teacher Sharon Hubers can't comprehend how her daughter stands charged with murder. Now, she's poised to stand by her only child as the defense puts on its case.

"Shayna Hubers has never said anything to anybody in this case other than, 'I had to do it to save my life. I did this in self-defense,'" defense attorney David Mejia tells the court.

Mejia doesn't deny that Shayna Hubers shot and killed Ryan Poston. But he must now convince the jury that Ryan was the aggressor that night. Mejia argues that for Shayna, it was kill or be killed. And he recites what Shayna told police:

"'He would've killed me. It was scary. I was scared. Oh, my God. That was frightening. I was scared. I could have died,'" he read aloud for jurors.

Sharon Hubers is the first to take the stand. She wants everyone to know about her wonderful daughter:

Sharon Hubers: She enrolled at Eastern Kentucky University. She decided she wanted to be a school guidance counselor.

While proud of her daughter -- "In every way, she's been brilliant" -- Sharon Hubers did not have a good feeling about Ryan. She tells the jury she was worried when she first met Ryan at his condo and saw his array of guns:

Sharon Hubers: Loaded guns, about -- there were two on the loveseat in the living room.

Sharon Hubers then testifies about the time leading up to Ryan's death, describing that frantic call from her daughter shortly after 3 a.m., some 18 hours before Ryan was shot. Shayna was at Ryan's and complained of chest pains:

Sharon Hubers: She was sick. She was in pain. There was fear in her voice.

So she hopped in her car and drove more than 80 miles to be at Shayna's side:

Sharon Hubers: She was shaking, she was grabbing her left arm.

Sharon Hubers testifies Ryan never came out of his bedroom, and Shayna refused to see a doctor. Clearly feeling better, Shayna and her mother later spent the day shopping. But much of that time, Shayna was furiously texting Ryan, writing, in part: "...I am being placed on medicine that will help my blood pressure." And later: "I am so thankful that my mom came and took me to the doctor..."

Snodgrass says none of this was true.

"Why was she saying these things?" Van Sant asked.

"To get his sympathy. If he felt sorry for her, then maybe she still had a chance," she replied.

That evening, Sharon Hubers left Shayna in front of Ryan's condo complex. Hours later, she receives another frantic call. Ryan was dead. She reveals to the jury that Shayna called her first -- before calling 911:

Sharon Hubers: She was hysterical, terrified, in shock ... Defense attorney David Mejia: What were your words to Shayna? Sharon Hubers: "Shayna, call 911 and tell them where you are and exactly what happened."

"Why would Shayna call mom instead of the police after this traumatic experience in having to shoot her boyfriend?" Van Sant asked Snodgrass.

"I have no idea why she would do that," the prosecutor replied. "This is the only thing that I can surmise from it is that she was trying to come up with her defense..."

[911 call] Shayna Hubers [crying]: He threw me across the room ... and ... and I was very startled. I was laying on the floor.

The night of Oct. 12, 2012, the defense argues, Ryan Poston had reached his boiling point.

"...he's got a lawsuit confronting him that he can't take," Mejia told the court.

Ryan was being sued by his former law partner. They point to Facebook messages he sent weeks before he died.

"Referring to the man who's suing him, Ryan writes: 'I want this piece of S destroyed. Bury him neck deep at low tide. Throw darts at his head,'" Van Sant read aloud to Birkenhauer. "That's a threat."

"I don't know if it's a threat or if it's a comment about his dislike for the individual that he's talking about," said the police chief.

The defense maintains these messages show Ryan had a dangerous temper fueled by drugs he was prescribed. Eight months before his murder he wrote to a friend: "The stuff they put me on fills me with rage from what I can tell."

"He was taking some pretty strong drugs," Mejia told jurors.

Ryan's friend, Allie Wagner, says Ryan had turned to the drugs to cope with the stress of the lawsuit.

"He said, 'I'm taking Adderall to wake up. And I'm taking Xanax to go to bed," Wagner told Van Sant.

But she insists he was still the same guy she met 10 years earlier.

"He -- was still normal. I mean, I saw him the day before he died. And he was fine," she said.

Now, a toxicologist takes the stand who says the mixing of those prescription drugs could have frightening effects.

"What these drugs do, they basically cause incidence of behavioral dyscontrol and hostile outbursts," Dr. Saeed Jortani testified.

The defense contends Ryan snapped, attacking Shayna.

[Police video] Shayna Hubers: ...and then this look came out of his eyes. He was like -- capable of anything. I think I told you he takes a lotta drugs.

Mejia reminds jurors what he believes happened -- that Ryan Poston was standing and moving when Shayna shot him six times.

"Even Shayna's own words do not support the theory that was presented in court," Snodgrass said. "She never said that he was standing."

[Police video] Shayna Hubers: ...when I shot him -- and he went like this literally [Shayna sits and hits her head against the table]. That's when I knew he was dead or close to it -- and twitching.

And what Shayna said next unknowingly made her the star witness for the prosecution:

[Police video] Shayna Hubers: I walked around the table [cries] and I think that's when I shot him in the head.I shot him probably six times. I shot him in the head. He fell onto the ground, he was laying like this [gets on the floor]. His glasses were still on. He was twitching some more. I shot him a couple more times just to make sure he was dead.

But a former medical examiner for the State of Kentucky, Dr. George Nichols, testifies Ryan could still have been a threat to Shayna even after he was shot:

Dr. George Nichols: He could move ... the chest wounds, the front and back wounds, the armpit wounds -- they would not cause him to -- to lose the ability to walk at least some or move some.

Shayna Hubers, the young woman who couldn't stop talking to police, doesn't take the stand. But her attorney will demonstrate how he believes the shooting went down.

DAMAGE CONTROL

As closing arguments begin, defense attorney David Mejia mocks the prosecution's claim that Shayna Hubers' obsession led to Ryan Poston's murder.

"She keeps callin' her boyfriend. And he can't get rid of her. She's a murderer. She keeps hounding him and hounding him with texts and emails. And so she's a cold-blooded murderer. Are you buyin' that?" Mejia addressed the jury.

Now, in a case that never lacks drama, Mejia brings the table where Ryan was shot into the courtroom and reenacts Ryan's shooting with co-counsel Rachael Neugent playing the role of Shayna Hubers

"Her statement was, he reached for the gun and I grabbed it. First shot to the head as he's reaching down to her as she's below him," Mejia demonstrated.

But in a dueling demonstration, Prosecutor Michelle Snodgrass argues that Mejia's theory is not supported by the forensic evidence.

"Again, the evidence doesn't lie," she told the court.

"The trajectory was in a downward, downward angle. There is no way that from the ground that shot occurred. It's just not physically possible," she demonstrated, holding the gun.

Snodgrass wants jurors to focus on Shayna's behavior, which she likens to a performance.

"When the cops walk out of the room, watch what the actress does," she said, showing jurors the police video:

[Police video] Lt. Fornash: Do you smoke?

Shayna Hubers: I will if I can. [Shayna starts crying; Lt. Fornash leaves room and she stops and looks at her nails]

"The minute he walks out of the room the crying stops ... that's the actress," Snodgrass told the court. "Within hours of putting six bullets into Ryan Poston and watching him die she danced and sang.

[Police video] Shayna Hubers: [twirling, snapping fingers]I did it! Yes, I did it!

"She showed us that she's a liar. She showed us that she's a manipulator. And most importantly, what she showed us on October 12, 2012, is that she's a murderer," Snodgrass continued.

The case goes to the jury shortly before 6:30 p.m. on April 23, 2015. Family and friends anxiously wait as deliberations go late into the night. Then, just before 11:30 p.m., a verdict is reached. It is time for Shayna to learn her fate.

Sharon and Shayna Hubers Sharon Hubers

"We the jury, find the defendant Shayna Hubers guilty of murder," Judge Fred Stine read aloud.

Guilty. Twenty-four-year-old Shayna Hubers, once a promising graduate student, is now a convicted murderer. For Ryan's family, there is enormous relief that justice has been served. For Shayna's mother, there is shock and disbelief.

"What was that moment like for you when you heard the word guilty?" Van Sant asked.

"That's difficult to explain, Peter," Sharon Hubers replied. "I was terrified. And, and it was surreal. I didn't see how on earth that could have been the outcome."

Court reconvenes the next morning, as jurors will now hear testimony from both sides to determine Shayna's sentence. Her lawyer asks the jury for lenience.

"The accomplishments and good deeds should not and cannot be ignored," Mejia told the court.

Katie Carter, one of Ryan's sisters, takes the stand to share her heartache:

Katie Carter: He made us complete. Without him there's always the chair that is gonna be empty. He will never be able to get married; he'll never be able to have kids; he'll never be able to go to his kids baseball games, He will never be able to have all the things he deserved to have in his life.

It takes the jury only about an hour to make its recommendation.

"We the jury, fix the defendant Shayna Hubers' punishment for the offense of murder at 40 years confinement in the penitentiary," Judge Fred Stine read aloud.

Forty years. The judge will later decide whether to accept the jury's suggested sentence. For Ryan's parents, it doesn't ease the pain of their loss.

"Shallow victory. Our son is dead," Lisa Carter told reporters gathered outside the courtroom.

"Never for one second did we ever think that there was any physical violence from a young man who had a kind and gentle heart," Jay Poston told reporters.

Three months later, they are back in court for a hearing.

The defense wants a shorter sentence for Shayna. So they're trying to prove that she was a victim of domestic violence at the hands of Ryan. That would make her eligible for parole after serving eight years. But first, under Kentucky law, the defense must prove the two lived together despite what she told police.

[Police video] Shayna Hubers: I don't live with him. Lt. Fornash: OK, is that his address? Shayna Hubers: That's his place. Lt. Fornash: Ok, what's your address, sweetheart?

Shayna had an apartment in Lexington, more than 80 miles away. Now, she takes the stand to try to convince the judge she was Ryan's live-in girlfriend by reading texts the two sent each other:

Shayna Hubers [reading texts in court] "Shayna says, 'I'm gonna fry boneless chicken breast for dinner. Does that sound good?' Ryan says, 'That sounds good.'"

Shayna Hubers takes the stand

But the prosecutor confronts Shayna with evidence that she was also seeing other men.

Prosecutor Snodgrass:Were you with 10 other men during this whole time that we're talking about, during 2012, 10 different men? Shayna Hubers:How are you saying was I with them, are you saying I was friends with them, or I was sleeping with them... Prosecutor Snodgrass: You slept with 10 different men during 2012. Shayna Hubers:In answer to your question, sure I may have slept with 10 guys in 2012, but I don't see how it's relevant to any of this s---.

The judge finds that Shayna and Ryan were not domestic partners. It is now up to the judge to issue his final sentence and the defense will make one last, desperate call for mercy.

ALLEGATIONS OF ABUSE

It has been nearly three years since Shayna Hubers shot Ryan Poston, including a final bullet as he helplessly twitched on the floor.

Now, at her sentencing hearing, her defense team wants to make sure the judge hears about Ryan's alleged history of aggressive behavior.

Defense attorney Rachael Neugent: Did she ever approach you and -- and discuss with you any acts of violence between her and Ryan? Nikki Carnes: Yes.

In a story not told at trial, Ryan's neighbor, Nikki Carnes, says a few months before the murder, Shayna came to her in tears:

Nikki Carnes: She had came to my door cryin'. And her arm probably from, like, here to here, she had a big red mark on her arm. She said that Ryan had slammed her arm in the door and threw her on the floor in the hallway.

"And when she told you this story, what did you see on her face?" Van Sant asked Carnes.

"She was clearly upset," she replied. "There were hand prints on her arm..."

But Shayna's cellmate Holly Nivens testified at trial that Shayna made the whole thing up:

Holly Nivens: She would purposely, like, pull her arms up so the neighbors would see bruises on her arms. Prosecutor Sheryl Heeter: Did she say how the bruises got there? Holly Nivens: She inflicted them on herself. Prosecutor Heeter: I'm, sorry? Holly Nivens: She inflicted them on herself.

Psychologist Ed Connor, an expert for the defense who evaluated Shayna, diagnosed her with narcissism and low self-esteem:

Ed Connor: I think Shayna was a person who had extreme difficulty with rejection and -- and tolerating it.

Now, it's up to Shayna to convince the judge that somehow, she was also a victim in this case -- a killer who deserves sympathy.

Shayna Hubers: It's sad when someone pushes you away and pulls you back in and pushes you away and pulls you back in," Shayna told the judge. "There were times when he had my head goin' 10 different directions to where I didn't even know if that was my boyfriend or not or what he was to me.

Shayna seems filled with resentment.

Shayna Hubers: I feel like I was led on. I feel like I was manipulated, used and abused. And no, Ryan didn't beat on me every day. I'm not-- I'm not gonna sit up here and exaggerate and lie and say that he did. But he did put hands on me a handful of times.

The prosecutor circles back to what she believes is at the heart of this case --rejection:

Prosecutor Snodgrass: Isn't it true that you sat here and you heard Dr. Connor say that you do not take rejection well? Shayna Hubers: Dr. Connor did say-- Prosecutor Snodgrass: And you-- Shayna Hubers: --that I don't take rejection-- Prosecutor Snodgrass: --were rejected, whether it had been earlier in the day when Ryan told you, "I don't want to see you," whether it was the other times where he said, "You know, we're done. This is it. No more. I need space," you were rejected by him, not just once but many times. Shayna Hubers: If I killed Ryan over rejection, he would've been b-- Prosecutor Snodgrass: Didn't ask you what you killed Ryan over. Shayna Hubers: --dead almost two years prior. Prosecutor Snodgrass: I asked you if you were rejected by him-- Shayna Hubers: Sure. I have been rejected. Prosecutor Snodgrass: --simple question. Shayna Hubers: I have been rejected. Prosecutor Snodgrass: Nothing further, Your Honor. Shayna Hubers: But if that were motive... Prosecutor Snodgrass: Nothing further your honor. Shayna Hubers: ...there'd be a graveyard -- full of men.

Did Shayna's plan to persuade the judge to be lenient backfire? As court reconvenes, she offers an apology -- for the first time:

Shayna Hubers: And I'm sorry to my family. And I'm sorry to my friends for letting them down. And I'm sorry for the money that my parents had to spend on attorneys.

But the young woman who was diagnosed a narcissist never apologizes to Ryan's family. Instead, she talks about herself:

Shayna Hubers: I do wanna help people. I do wanna be something better.... And I do want to continue to grow and learn. And I just don't think that a 40-year sentence will help me ..."I don't think it would benefit be any; I don't think that it would rehabilitate me any.

Now it's Judge Fred Stine's turn to speak ...and he has some choice words for Shayna.

"What I think happened in that apartment was little more than cold-blooded murder. It was probably as cold-blooded an act as I've been associated within the criminal justice system in the 30-plus years I've been in it," Judge Stine said. "That's about all there is to say."

He upholds the jury's recommended sentence of 40 years.

As Ryan's family leaves the courthouse, they can barely contain their anger.

"Is there anything you want to say to Shayna?" a reporter asked.

"Oh, God no! Rot in hell," Jay Poston replied. "She is going where she deserves to be and where she's going her mommy can't help her."

"Mommy'll always be there," a tearful Sharon Hubers told Van Sant.

Shayna's mother will never accept that her beloved, brilliant daughter is anything but a victim who had to defend herself.

"I'll draw my last breath helping that baby," Sharon Hubers said. "She doesn't deserve this. She's done nothing wrong."

But this emotional roller coaster is not over. One year after Shayna's conviction, there is a dramatic development no one predicted.

Shayna is granted a new trial after her lawyer discovers a member of the original jury was a felon. According to Kentucky law, he should have been barred from serving.

"We will jump through as many hoops as we have to jump through to get justice for my son. If we have to do this a hundred times we will do it a hundred times," Jay Poston said in July 2017.

Ryan Poston's family is braced to endure more painful testimony. And Shayna Hubers is about to show just how far she'll go to win back her freedom.

A NEW TRIAL



Shayna Hubers' second trial begins on Aug.14, 2018 – almost six years after Ryan Poston's death.

A lot has changed. Shayna is now 27 and married. In a brief jailhouse ceremony in June, Shayna wed a convicted drug trafficker named Richard McBee. The two somehow met at the Campbell County Jail where they were both locked up.

In yet another twist, McBee sometimes identifies as a transgender woman named Unique Taylor. You may recall after killing Ryan, Shayna worried about finding love:

[Police video] Shayna Hubers: I don't know if anyone will want to marry me if they heard that I killed my boyfriend in self-defense.

Now newlywed Shayna is back in court. And that same disturbing interview with police remains the strongest evidence against her:

[Police video] Shayna Hubers: He's very vain ... and wants to get a nose job. Just that kinda person and I shot him right here. I gave him the nose job he wanted.

The defense, led this time by attorney David Eldridge, is again claiming Ryan was abusive:

"Ryan was very aggressive with her," Eldridge told the court.

"What started out as that evening as a normal evening ended that night with Mr. Poston being both sexually and physically violent," he continued.

Eldridge takes the jury on an X-rated journey to prove his case:

"She could not reach orgasm when they had sex …it is a constant criticism by Mr. Poston," said Eldridge.

"OK, call your next witness," said the judge.

"We call Shayna Hubers," said Eldridge.

It's a risky move, but Shayna takes the stand, telling graphic tales of rough sex that sometimes turned kinky against her will:

Shayna Hubers: And I started to bleed. And it, it was painful. Shayna Hubers: Ryan did something I didn't want him to do -- David Eldridge: How did that experience make you feel? Shayna Hubers: It felt degrading.

She claims Ryan often humiliated her:

Shayna Hubers: He told me that it was unattractive that I couldn't orgasm.



Despite the passage of time, Shayna easily recalls specific dates and details of alleged unprovoked abuse by Ryan.

Shayna Hubers: I was woken up to him pushing me out of the bed … and he just started screaming at me.

Why would Shayna stay with Ryan?

Dr. Thomas Schacht: Borderline personality disorder is a chronic long-term condition.

Defense psychologist Thomas Schacht says she has a personality disorder and PTSD from childhood sexual abuse. There are no police reports to support Shayna's claims:

Dr. Thomas Schacht: Ms. Hubers' psychological condition was seriously abnormal.

Shayna admits she did not handle their break-ups well:

Shayna Hubers: I would often send him countless text messages. David Eldridge: Did you ever show up at his condominium uninvited? Shayna Hubers: Yes.

When she showed up at his condo the night of October 12, 2012, Shayna claims, Ryan exploded in anger and attacked her:

Shayna Hubers: He picked me up … and threw me from the doorway of his bedroom into the other room … He screamed at me, "you're a f---ed up person, and you're a f---ed up person because you were touched when you were a little girl.

After the fight had moved into the dining area, Shayna claims she was left crying on the floor:

Shayna Hubers: He was reaching across the table. And I don't know if he was reaching for the gun or reaching for me, but I was still sitting on the floor at this point in time. And I got up off the floor, and I grabbed the gun, and I shot him.

It's not the same story Shayna told when she called 911.

Shayna Hubers to 911: …and he reached down and grabbed the gun and I grabbed it out of his hand and pulled the trigger.

Prosecutor Michelle Snodgrass pounces:

Prosecutor Snodgrass: Please make sure we get this right …Your story was different. Shayna Hubers: After all these years, I really don't remember the 911 call. Prosecutor Snodgrass [snickering]: But you remember every other detail, every other detail of a relationship that started in 2011.

Snodgrass confronts Shayna with other inconsistencies:

Prosecutor Snodgrass: In fact, you often described Ryan to your friends as being calm, didn't you?" Shayna Hubers: Ryan could be calm at times. Prosecutor Snodgrass: You told them that he was patient and kind. Shayna Hubers: Ryan was sometimes patient, kind and nice, yes. Sometimes he wasn't. Prosecutor Snodgrass: You want to tell the jury what you told your friends?

Shayna Hubers

She points out Shayna was a willing participant in the kinky sex:

Prosecutor Snodgrass: Isn't it true that you told multiple friends how it was the best sex of your life? Shayna Hubers: I'm sure I said that. Prosecutor Snodgrass: The way he looked at you was unreal. You said that. Shayna Hubers: I'll take your word for it. I don't remember it. But, yes. [Police video] Shayna Hubers: I shot him probably six times.

And Snodgrass reminds Shayna of what she told police after pumping six bullets into Ryan:

[Police video] Shayna Hubers: He was twitching some more. I shot him a couple of more times just to make sure he was dead 'cause I didn't wanna watch him die. Prosecutor Snodgrass [in court]: And you told officers that it was too painful for you -- Shayna Hubers: I said that. Prosecutor Snodgrass: -- to watch him die.

Now, six years later, that story has changed as well:

Shayna Hubers [in court]: I also, when I first shot him, wasn't sure were the shots had entered or I had just made him more angry.

The jury deliberates for nearly five hours.

"We the jury find the defendant Shayna Hubers guilty of murder…" the judge read aloud in court.

Shayna Hubers is guilty of the murder of Ryan Poston for a second time. The jury reconvenes the next day to decide on a sentence.

Katie Carter, a sister of Ryan Poston, holds a stuffed bear made of one of her brother's shirts. The bear plays a voicemail message from Ryan.

Once again, Ryan's father and sister have to find the words to describe their loss:

Jay Poston: Ryan had a heart of gold. He never, ever left me without kissing me on the cheek and telling me he loved me. Katie Carter [crying, holding a stuffed bear]: This is Ryan's shirt. Katie pulls a string on the bear: "You've reached attorney Ryan Poston. I'm sorry. I'm unavailable right now. If you could leave a message, I will call you back as soon as possible. Thank you."

Katie Carter [playing voicemail message in court]: That's it. That's all we have. A voicemail.

Shayna's devastated mother hopes the jury will show mercy.

Sharon Hubers: My child's life has also been taken. Her family also grieves. I'm not lessening, or taking away from, or trying to say that I don't understand the grief of this family, because I do.

But the defense's bid for leniency fails.

"We the jury fix the defendant Shayna Hubers' punishment for the offense of murder at life imprisonment," the judge read aloud.

A life sentence – more than the 40-year sentence Shayna received at her first trial. Ryan's family is relieved.

"This is justice," Peter Carter said standing with family outside the courtroom.

"This is justice from the system," Lisa Carter said.

"That's about all," Peter Carter continued. "There will never be closure. We will never walk through that door again."

Ryan Poston

And they will always wonder about what might have been.

"I will forever miss the possibilities," Jay Poston said. "We will never know the incredible possibilities that Ryan Poston would have given to this earth. He was a tremendously gifted young man."

Judge Dan Zalla upheld the jury's life sentence.