Young Colorado mom and skilled pilot Kelsey Berreth vanished on Thanksgiving 2018 after being last seen with her daughter at a supermarket near her Woodland Park home.

Before the investigation would be through, her fiance, Patrick Frazee, and a woman to whom he allegedly was romantically tied would be arrested in connection to her death.

Below is a timeline of the investigation, starting in November of last year and going through to today:

Thursday, Nov. 22

Surveillance footage from Safeway supermarket showed Berreth shopping for groceries with her 1-year-old daughter about 12:30 p.m., police said.

“That’s the last time Kelsey was seen,” Woodlawn Park Police Chief Miles De Young would go on to tell reporters.

De Young also noted that Berreth’s fiance and the father of her daughter, Patrick Frazee, told investigators he saw Berreth that day when she handed off their child to him.

Sunday, Nov. 25

Berreth’s employer, Doss Aviation, received texts from her cellphone saying she would not be at work for the next week, police said. Berreth worked as a pilot instructor.

Investigators were able to determine Berreth’s cellphone pinged that day on a tower near Gooding, Idaho, about 600 miles from her home in Woodland Park.

Frazee told police he received a text from Berreth’s phone that same day. Investigators have not revealed what that message said.

Sunday, Dec. 2

Kelsey’s mother, Cheryl-Lee Berreth, reported her daughter missing after being unable to reach her. Cheryl-Lee reached out to Frazee, who called her back and said he hadn’t heard from her since she had last texted.

Officers with the Woodlawn Park Police conducted a community care takers search on Kelsey’s home, which was empty. Her cars, her clothes and her toothbrush all appeared untouched since Thanksgiving, authorities said.

Monday, Dec. 3

The Woodland Park Police Department sent out its first appeal to the public in the hopes that someone would have information about Kelsey’s whereabouts.

“Please contact the Woodland Park Police Department at 719-687-9262,” they wrote.

Wednesday, Dec. 5

Kelsey’s loved ones created the “Missing Mother – Kelsey Berreth” Facebook page to spread the word about her disappearance.

The Woodland Park Police note Kelsey had last been seen wearing a white shirt, gray sweater, blue pants that may have been jeans, white shoes and had a brown purse.

Thursday, Dec. 6

Kelsey’s family noted it would be out of character for her to not let anyone know if she planned on making flying cross-country, regardless of her experience in the air.

“She does not own a plane nor do we know of any local friends that she would borrow one from,” they wrote on Facebook. “I don't believe she has ever made a flight without filing a flight plan. We do realize that it is possible to rent a plane, but I believe someone would be missing it by now.”

Friday, Dec. 7

A prayer vigil was held for Kelsey outside her brother’s home in Tacoma, Washington. Friends and neighbors came together to show their support, holding candles and singing “Silent Night,” video of the gathering showed.

“Please keep praying!” her family said on Facebook. “We need to find Kelsey!”

Monday, Dec. 10

The Woodland Park Police Department was joined by Cheryl-Lee for a press conference to share what they know so far.

De Young said the department is working with numerous law enforcement authorities, including the Colorado Bureau of Investigation, the FBI and officials in Gooding, Idaho.

All planes at her place of work have been accounted for, and there was nothing that indicated Kelsey flew somewhere.

No one had been identified as a suspect in Kelsey’s disappearance, De Young said.

He said that while Kelsey’s fiancé, Frazee, was cooperating with police, he declined to attend that day's press conference.

“That’s a question you would have to ask him,” De Young said of Frazee’s decision to not attend.

Frazee and Kelsey’s young daughter was with Frazee at the time, De Young said. Kelsey has never lived with Frazee, her mother told reporters.

“I’d just like to talk to you a little bit about Kelsey,” she said. “She’s not the kind that runs off. This is completely out of character.

“Kelsey loves her god, she loves her family and friends, and she loves her job,” Cheryl-Lee continued. “She’s reliable, considerate and honest. … She doesn’t run off, and someone knows where she’s at.”

Tuesday, Dec. 11

Woodland Park police released the last-known footage of Kelsey before she disappeared. In the video, the young mother can be seen entering the Safeway supermarket. She carries her daughter in what appears to be a car seat that she then placed into a shopping cart before walking further into the store, the video shows.

Thursday, Dec. 13

Kelsey's mother, Cheryl-Lee, spoke to NBC, saying she was hopeful her daughter will be found.

“I can’t think of anywhere she’s gone where she hasn’t told me,” Cheryl-Lee told NBC. “It’s just not in her character to do something, to just take off and be gone.”

Cheryl-Lee said she spoke with her daughter twice on Thanksgiving, including once when Kelsey needed the details of a recipe.

“Her voice was fine,” her mother said. “It was a normal day for her.”

Cheryl-Lee said her daughter did not live with her fiance, Frazee, but that they have a strong bond.

“The relationship has been good,” said Cheryl-Lee. “They’re loving.”

Frazee's attorney, Jeremy Loew, told NBC his client was cooperating with police. Frazee voluntarily released his phone to be searched by investigators and has provided cheek swabs for DNA samples, he said.

Frazee wasn't present at a press conference held on Kelsey's case Monday because he only learned of it an hour before, his attorney said, noting he would have gone had he been given more notice. Loew said he also advised Frazee against speaking publicly to avoid tainting the investigation.

Resolute that someone somewhere knows something, Cheryl-Lee said she's committed to remaining positive.

“I still know somebody knows where she’s at,” Cheryl-Lee said. “Somebody has seen her. There’s more information out there. Somebody just needs to realize, recognize, say something.

"In the back of mind, sure, there's a possibility something else could have happened," she continued. "But it does me no good to go down that road. And I don't think it does Kelsey any good either."

The Woodland Park community gathered that evening for a candlelight vigil at the flagpole at Memorial Park in a show of solidarity to Kelsey's loved ones.

"We just want to spread love and hope and let Kelsey and her loved ones know that we're here for them," vigil organizer Amber Overton told The Denver Channel.

The dozens of people who came together were joined by Kelsey's mother, as well as De Young, who told the crowd a reward is being offered for information in the case. Specifics were reportedly not provided.

Friday, Dec. 14

Law enforcement officers executed a search warrant at Frazee's home, officials said.

Deputies with the Teller County Sheriff’s Office cut the lock on Frazee’s gate in Florissant before beginning their search of his home Friday, KRDO-TV reported. More than 75 law enforcement officials participated in the search.

Officials said the search could take up to three days. Frazee was at the property and was not under arrest, deputies told KXRM-TV.

But Frazee was never asked to voluntarily participate in the search executed at his home Friday, Frazee's attorney told the news station.

“We encourage law enforcement to take whatever steps it deems necessary to find Kelsey Berreth and to be able to exclude Patrick Frazee as a possible suspect in this missing person investigation,” he said in a statement. "Mr. Frazee will continue not to participate in any interviews with the media and instead focus on parenting the child he shares with Ms. Berreth.”

Sunday, Dec. 16

Authorities completed the search at Frazee's home. It was not immediately not clear what, if anything, they may have found.

The Woodland Park Police Department announced a $25,000 reward for any information about Kelsey's whereabouts. The reward came from an anonymous donor, authorities said in a press release.

Tuesday, Dec. 18

Investigators briefly returned to Frazee's property Tuesday, but police said the visit was a routine follow-up, The Denver Post reported.

Authorities said they were continuing to "make steady progress" and were following multiple leads into Kelsey's disappearance.

The warrant issued in the search was sealed and no details were available to the public.

As investigators continued their search for Kelsey, a friend of Frazee's came to his defense.

Sonja Oliver, who says she has known Frazee for five years, told Inside Edition, "I've always considered him to be a gentle soul. Soft-spoken and just really down to Earth and practical."

Oliver said she “couldn’t imagine him doing anything that would harm anyone.”

When asked by Inside Edition if she believes he had anything to do with Kelsey's disappearance, Oliver said, “I just can't imagine Patrick doing anything like that.”

Frazee's attorney told Inside Edition his client and Kelsey's relationship was largely positive.

“Like most relationships it has ups and downs, but for the most part, it's a good relationship,” he said.

Friday, Dec. 21

Frazee was taken into custody about 7 a.m. local time and was charged with murder and solicitation to commit murder, Woodland Park Police Chief Miles De Young said at a press conference.

"Sadly, we do not believe Kelsey is still alive," he told reporters.

Investigators had not yet located Kelsey's body, but they believe she may have been killed in her Woodland Park home.

De Young said police had conducted multiple interviews that gave them enough information to implicate Frazee in her death and obtain a warrant for his arrest. A multi-jurisdictional task force made up of numerous law enforcement agencies, including the FBI, served the warrant at Frazee's 35-acre ranch in Florissant.

His and Kelsey's 1-year-old daughter was placed in protective custody Friday before being reunited with her mother's family, De Young said.

Authorities confirmed that Kelsey's cellphone is in fact in Idaho, but were not able to elaborate on how it got there.

Saturday, Dec. 22

Authorities in Twin Falls, Idaho, said in a statement that its officers helped the Colorado Bureau of Investigations and the FBI "to prepare and serve several search warrants as well as processing some items of evidence."

The department did not say what evidence may have been found.

Twin Falls' Sheriff Tom Carter and Police Chief Craig Kingsbury said in a joint statement, “We are pleased our organizations were able to provide the assistance and support requested by the FBI, CBI, and the Woodland Park Police Department.”

Thursday, Dec. 27

Shackled and looking disheveled, Frazee appeared in court for an emergency custody hearing regarding his daughter.

The judge granted temporary custody to Kelsey's parents.

Monday, Dec. 31

Frazee was formally charged with Kelsey's murder. The complaint, which featured little in the way of details, included three charges of solicitation to commit murder, as well as two charges of first-degree murder.

Fourth Judicial District Attorney Dan May said that the two murder charges represent two separate theories of how Kelsey was killed. One of the murder charges mentions an accusation of robbery, indicating she was killed during the commission of a separate crime.

The other murder charge alleges Frazee himself deliberately caused the death of Kelsey with intent to do so.

“Obviously, there’s only one murder in this case,” May told KMGH-TV. “Under Colorado law, we file separate counts under different theories of first-degree murder. We filed under two theories: One is deliberation for murder. And the other is felony murder.”

Thursday, Jan. 3

A report emerged that an Idaho nurse, Krystal Jean “Lee” Kenney, 32, was being investigated for possibly disposing of a cellphone belonging to Kelsey.

Friday, Jan. 4

Kelsey's parents, Cheryl-Lee and Darrell, filed a wrongful death lawsuit, seeking unspecified damages against 32-year-old Frazee, according to The Associated Press.

Monday, Feb. 4

Kenney planned to plead guilty to at least one count in a court appearance later that week as part of a deal struck with prosecutors in the case, according to ABC News.

Friday, Feb. 8

Kenney was charged with one count of felony evidence tampering and pleaded guilty after agreeing to testify against Frazee, KOAA-TV reported.

Prosecutors said Kenney destroyed evidence related to Kelsey's disappearance between Nov. 24 and Nov. 25, 2018. Authorities have not released information about the evidence Kenney allegedly destroyed. Court records containing details about the evidence that led to the arrests of Kenney and Frazee remain sealed.

“I learned that Patrick Frazee had committed a homicide on approximately Nov. 22 in Teller County," Kenney said in a statement read by Fourth Judicial District Attorney Dan May at a press conference following her court appearance Friday, KOAA-TV reported. "I knew that law enforcement would be investigating that crime. I moved the victim’s cell phone with the intent to impair the phone’s availability in the investigation.

"I had no right or authority to move the victim’s cell phone that occurred between Nov. 24 and Nov. 25, 2018 in Teller County.”

As part of her plea deal, Kenney cannot speak to the media.

Kenney will be sentenced after the conclusion of Frazee’s trial and faces as little as probation, or as much as 18 months on prison. If the judge determines there was an aggravating factor in the case, her sentence could be up to three years.

Officials would not comment on the nature of Kenney and Frazee's alleged relationship, nor would they discuss the status of the search for Berreth's body. Court records containing details about the evidence that led to the arrests of Kenney and Frazee remain sealed.

Friday, Feb. 15

Kelsey’s parents updated the wrongful death lawsuit they filed against Frazee, saying a custody dispute was likely a motive to kill their daughter.

“Upon information and belief, Frazee had motive to kill Kelsey in that he wanted full custody of [their daughter] KB and/or Kelsey to leave KB with him and Kelsey would not agree,” said the amendment, which was filed in a U.S. district court Friday.

The amendment, which was made to a January wrongful death lawsuit filed by Kelsey’s mother and father, also alleged that Frazee “had an opportunity to kill Kelsey or have Kelsey killed in that he had her keys and, because he had her gun, she was vulnerable to an attack.”

Kelsey’s parents said in the court filing they grew concerned after their daughter didn’t respond to calls or texts for a week. Cheryl-Lee said she called Frazee Dec. 2 to ask about Kelsey.

“Frazee responded with ‘here’s the story …’ and proceeded to knowingly and deliberately communicate … false statements, misrepresentations, and/or calculated omissions,” the update said.

Frazee allegedly told Kelsey’s mother that he and Kelsey broke up on Thanksgiving, that Kelsey agreed to evenly share custody of their daughter with him and that when she didn’t respond to a text he sent, “he figured she had put her phone on do-not-disturb so that she could study.”

When pressed for more details, Frazee allegedly said “Kelsey may have flown somewhere with a friend or co-worker,” the amended complaint said.

At one point, Frazee allegedly told Cheryl-Lee he “had enough and wasn’t going to deal with things anymore.”

The Berreths asked for a jury trial in the wrongful death lawsuit, which was filed in a federal civil court because Frazee lives Colorado, while Kelsey’s parents live in Idaho.

When reached for comment by CNN, Frazee’s attorney Ed Farry declined to respond to the allegations in the amended complaint, saying "any such response will be made through a court filing.”

Tuesday, Feb. 19

Colorado prosecutors alleged Frazee beat Kelsey to death with a baseball bat after trying unsuccessfully to persuade his new girlfriend to end her life. Frazee is accused of wrapping a sweater around Kelsey's head and bashing it in with a bat before burning her body in a water trough, according to testimony at a preliminary hearing, CNN reported.

Frazee allegedly tried convincing Kenney to steal powerful drugs they could use to poison Kelsey's coffee, investigators reportedly said. Frazee allegedly told Kenney he wanted her to “get rid of Kelsey,” saying Kelsey was a terrible and abusive mother to their toddler daughter as well as a drug user.

Police said Kenney told them Frazee gave her Kelsey's address and her photo, and Kenney drove to the 29-year-old flight instructor’s home after picking up Starbucks coffee. Kenney allegedly said she knocked on Kelsey's door and lied about who she was when Kelsey answered, but said she was unable to go through with the plan. Authorities said Kenney told them when she told Frazee she couldn’t poison Kesley, he grew angry.

It was apparently one of three instances in which Frazee allegedly tried convincing Kenney to kill Kelsey before he is accused of taking matters into his own hands.

Police said Kenney said that while she was not involved in the actual attack, which investigators believe occurred in Kelsey's apartment last Thanksgiving, she was involved in the cover-up.

Gregg Slater, an agent for the Colorado Bureau of Investigation, testified Tuesday that Kenney said Frazee asked her to go to Kelsey's apartment to clean up blood. Frazee even asked Kenney to search for a tooth near a vent in the home, Slater reportedly said.

While she spent hours scrubbing the apartment, which she apparently described as “horrific,” Kenney told police she refused to help Frazee dispose of Kelsey's body and so he took it to a farm in Fremont County, Slater said. Frazee then allegedly left Kelsey's body, which he had stuffed into a black tote bag, in a stack of hay while he celebrated Thanksgiving.

"You don't know how hard it is to have Thanksgiving dinner after killing her," Slater said Kenney told them Frazee said.

Frazee later allegedly put the body in a water trough, where he doused it in gas and added wood before lighting it on fire, Slater testified. He is believed to have left the remains at either a dump or in a river, Slater said.

But police investigating Kelsey's disappearance said they found blood in her toilet, the outside of her bathtub, the bottom of a trash can, on the walls, the floor, a towel rack, the vanity and an electrical outlet.

The blood found matched a DNA profile developed with samples taken from Kelsey's family, Slater said.

Frazee on Tuesday was hit with additional charges, including tampering with a body and counts related to a crime of violence. He has not yet entered a plea.

Tuesday, Feb. 26

Crews searched the Midway Landfill for Kelsey's remains as well as any other evidence possibly connected to the missing mother. The search was expected to take several months to complete, sources told ABC News.

Waste Management of Colorado confirmed to ABC News in January the Colorado Bureau of Investigation contacted them “regarding a potential search at Midway Landfill.” The agency said it is fully cooperating.

Wednesday, March 6

Details in the case against Frazee were revealed in newly released search warrants.

Frazee's phone continued to receive texts from Kelsey's phone after police say she was killed at her Colorado residence on Nov. 22, Thanksgiving Day, the documents show. Some were run of the mill, such as asking Frazee to take care of their 1-year-old daughter or talking about how she was feeling tired.

But on Nov. 24, the tone of the messages changed. "If this is truly what you want," read a text from Kelsey's phone to Frazee's, "I’ll respect your wishes and give you space. Let me know if you change your mind. I’ll leave you alone now, you can call me when you decide what you want to do."

"Do you even love me?" a text from Kelsey's phone to Frazee's read the next day, Nov. 25.

"Why would I bend over backwards and stand behind you thru everything if I didn't? So to answer your question yes I do," Frazee replied.

The text messages were part of what investigators call a monthslong plot to kill Kelsey, beginning back in September.

The documents also state that Kelsey's mother, Cheryl-Lee, discovered a suspicious stain on the underside of a toilet seat in her home, prompting investigators to test it for blood. It tested positive, leading them to do a more detailed search of the rest of Kelsey's home, and traces of blood were ultimately found nearly everywhere — on the floor, the towel rack, the ceiling above the toilet, the walls, according to the search warrants.

Cheryl had already reported her daughter missing on Dec. 2, having not physically spoken to her since Nov. 22. When she contacted Frazee about Kelsey, he told her they had parted ways and he had not seen her since Thanksgiving.

Asked by investigators about Frazee, Cheryl shared a story of his behavior immediately after their daughter's birth. There were complications during the birth, according to Cheryl, and the child had to be taken for treatment immediately afterward. Frazee "became so upset and verbally abusive with the nursing staff that Social Services was notified," according to the search warrants. Cheryl added that Frazee later said he could have "killed" the nurse who reported him.

Clues that pointed investigators to Frazee include cellphone records showing that while Frazee and Kelsey were allegedly texting after when investigators say she died, the two phones were in close proximity.

On Nov. 23, the day after the alleged murder, call logs show Frazee made a call to Kelsey's cellphone. But the calls use the same cell site near Frazee's home, indicating that the two phones remained nearby, according to the documents. This pattern continued until Nov. 25, at which point Kelsey's phone had moved into Utah and finally ended up in Idaho.

The last ping from Kelsey's phone was in Idaho, where it is now known that Kenney disposed of it, by her own admission.

Wednesday, Aug. 21

Frazee may be planning to indicate someone else was behind Kelsey's death when he strands trial this fall, court documents suggested.

A P-15 form, or a “Proposed Order to Endorse Alternate Suspect,” was filed on July 25 in Teller County District Court in the case of “People of the State of Colorado v. Patrick Frazee.”

The court document filed by Frazee’s defense does not mention whom he could potentially blame for Berreth’s killing. Frazee’s trial is expected to begin Oct. 28. His attorneys have requested a jury pool of about 300 people due to the publicity of the case.

Friday, Oct. 4

New details on the investigation into Kelsey’s killing were revealed on “48 Hours.”

“When they got the search warrants and went in there specifically with a team … they found blood in the bathroom. Some of that blood was Kelsey’s,” an authority familiar with the details of the case told “48 Hours” correspondent Nikki Battiste said on the show.

“There was also a mix of male and female DNA in the sink,” she continued. “But the key is, that male DNA did not belong to Patrick Frazee. The physical evidence in this case so far is incredibly weak.”

Numerous people connected to the case were interviewed for the piece, including those closest to Kelsey.

“Once I heard that he had been arrested, it just solidified that feeling deep down that I knew that she wasn’t coming back,” a friend of Kelsey’s said.

Kenney’s best friend, Michelle Stein, also was interviewed. She recalled having a disturbing conversation with Kenney before Kelsey disappeared.

“She told me he had asked her to take care of his baby mama,” Stein told Battiste. “And so I was like, I was in shock at first, because, who says that? She said, ‘Yeah he asked me if I would kill the mother of his baby.’”

Kenney is the key to the prosecutors’ case against Frazee.

“There’s poison coffees, there’s a baseball bat, scented candles, blindfold, phones that are pinging all over Colorado and in Idaho, all of the clues in the case that investigators are getting are from one person,” KKTV-TV reporter Ashley Franco said of Kenney to Battiste. “She’s the bread and butter to this case. She’s the only person in the world that they have to possibly convict Patrick Frazee. Do we know if any of this is true? Can anyone believe it?”

Friday, Nov. 1

Frazee's trial set off a series of chilling testimony from those who knew the couple. A longtime friend of Frazee named Joseph Moore took the stand and said Frazee told him, “I figured out a way to kill her. ... No body, no crime, right?”

Krystal Lee, Frazee's former girlfriend, took the witness stand and told jurors that Frazee called her on Thanksgiving to say said she needed to come over and clean up a mess at Berreth's condo. Lee said she saw blood on the living room floor, splattered on the walls, behind the couch and in the kitchen.

She feared Frazee would also harm her, she said, so she did as he asked. Afterward, Lee said Frazee claimed he told Berreth they were going to play a game, and he blindfolded her and then had her guess the scent of various candles, Lee testified. Then he hit her in the head with a baseball bat, she said.

"He just said he swung away, and that it was really hard," Lee told the court. The two took the trash bags and a container holding Berreth's body to Frazee's ranch, where he burned the contents, she said.

Margaret Luce, a customer of Frzee's horseshoeing business, said Frazee had told her he wanted to raise his and Berreth's 1-year-old daughter without Berreth. “He said he just wants her gone so he can raise Kaylee with someone else,” Luce said.

Frzee has pleaded not guilty to first-degree murder, solicitation to commit first-degree murder, tampering with a deceased human body and crime of violence in connection to Kelsey's presumed death.

Anyone with information is asked to contact the Woodland Park Police Department at 719-687-9262 or Kelsey@city-Woodlandpark.org.

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