In prison, 18-year-old Ashlee Martinson said she feels freer than she did at home in Wisconsin.

It was there, she said, that a lifetime of physical, sexual and psychological abuse culminated into one horrific moment last year -- the moment she fatally shot her stepfather, Thomas Ayers, 37, and fatally stabbed her mother, Jennifer Ayers, 40, more than 30 times. Then she locked her three younger siblings in a bedroom in their home in the tiny town of Piehl, in northern Wisconsin, and ran, police said.

Following a multistate manhunt, police arrested Martinson in Indiana, where she fled with her boyfriend. In March, she ultimately pleaded guilty to second-degree homicide and is serving 23 years in prison.

"I'm happy," Martinson said during an exclusive interview with Crime Watch Daily, which aired Tuesday. "I know that sounds crazy, because I'm in prison, but I feel like I'm free. I can wake up every day and know that I am safe."

Seemingly for the first time since she was sent to prison, Martinson is telling her own story -- one about a teenage girl, abused for years by her mother's boyfriends as her mother stood by them.

"I'm not a monster," she told Crime Watch Daily. "I never meant any of this to happen. It doesn't make it right, what happened. But I was just a girl, an abused girl, who was forced to make a really bad decision.

"I'm not the monster that they portrayed me to be."

Accounts from Martinson and professionals who interviewed her after the incident portray a teenage girl who, after years of alleged abuse, suffered severe depression and post-traumatic stress disorder, The Washington Post reported earlier this year.

Her online presence, it seems, revealed the darker side.

Martinson, who went by the pseudonym "Vampchick" on her blog titled Nightmare, purportedly posted a poem days before her parents' deaths about torturing and killing people, according to People.

"I clean the dry blood off my tools from a previous session," she wrote in a poem called "Unworthy," according the Daily Mail. "The last body has been disposed of just hours before, yet I have not been satisfied with the pain, agony and blood.

"I bend down as they start to wake.

" 'Welcome to hell.' I whisper in her ear. 'Never again will you see the light of day.' "

Authorities confirmed last year that the blog that had been linked to Martinson was indeed associated with her; but they did not know whether the content posted under the pseudonym "Vampchick" was her original work.

The blog has since been taken offline.

On March 7, 2015, a day after her 17th birthday, Martinson got into an argument with her parents, she later told police.

"I was supposed to move out, in with one of my friends," she told Crime Watch Daily. "I was all packed up and ready to go that day. But my stepdad stopped me."

Her younger sister told authorities that Martinson's mother and stepfather had discovered that the teenager had a 22-year-old boyfriend and sent him a message on Facebook telling him to stay away from their daughter, according to court documents.

"As her parents," they wrote, "we can press charges."

They took away Martinson's keys and cellphone, according to the documents, and forbid her from seeing him again.

"Work and school was my freedom. He was going to take it all away," Martinson recently told Crime Watch Daily. "I was going to be 100 percent imprisoned in that house, and I believed him."

She said she grabbed her stepfather's shotgun and went into her bedroom. She was thinking about suicide, she said.

"I was sitting on my bed. I even had the end of it in my mouth, playing with the trigger," she told Crime Watch Daily. "Then I heard my stepdad."

"I was scared of him. I am messing with his gun -- one of his precious belongings. And I thought he was going to snap on me. And I just reacted. ... I raised the gun and I pulled the trigger."

"I start running down the stairs," she added. "I was on the first landing and that's when I saw my mom. She ended up grabbing this decorative knife that was on a shelf and the next thing I knew the knife was in my leg."

That moment, her worst memories started playing like "a movie reel" in her head, she told Crime Watch Daily.

"Memories of all the bad things that happened to me, that she put me through," she said. "And I remember stabbing her once, then twice, and then I black out and the next thing I knew there was blood everywhere."

Then, she told Crime Watch Daily, she looked over and saw her stepfather.

"Seeing him scared me more," she said. "I thought he was going to get up and he was going to see what I did. I was scared what he was going to do.

"I remember pointing the tip of the gun against his head and I pulled the trigger. Boom. And in that moment, I felt the chains break around me. I was free. For the first time in my life, I felt that I was free.

"He couldn't hurt my sisters anymore. He couldn't hurt me anymore. He couldn't hurt anyone."

Parts of Martinson's story, however, vary from the account in court records. For example, witnesses told police there were two gunshots close together but Martinson said she shot her stepfather once, then stabbed her mother, then shot him a second time.

Martinson told investigators her mother's boyfriends had been abusing her since she was a young child.

One of them, she claimed, raped her when she was 9 years old, according to the court documents.

"He was extremely abusive," she told Crime Watch Daily. "That man, that man took everything from me."

"She would send him in to tuck me in at night or to give me a bath," she said of her mom. "She knew. She knew what was going on."

When Thomas Ayers came into the picture, Martinson said in the interview, he wasn't much different from the others.

"You know how people say that I'm the monster?" Martinson told Crime Watch Daily. "He was the monster."

Martinson said although Thomas Ayers did not hurt her physically, he would abuse her mother and sisters to punish her.

"That is exactly what he did," she said. "That was my punishment. That was the way he knew he could hurt me."

Over the years, Thomas Ayers had been accused of assault, kidnapping, child enticement and party to the crime of sexual assault of a child younger than 15, according to court documents, which noted that he "had numerous prior arrests and convictions."

Two of Martinson's sisters told authorities that Thomas Ayers would hit them "very hard" with "a thick belt and his hand" -- on several occasions until "their buttocks nearly blistered," according to the documents. They said he had choked them and had punched one of the girls in the face, giving her a black eye.

One of the girls said Thomas Ayers told them he threw their puppy around and "shot and killed him, and fed him to a bear."

He also abused Martinson's mother, they said.

The teenager told police that her stepfather once climbed on top of her mother, pinned her down, put a gun to head and pretended to sexually assault her, saying, "Just like your father," according to court documents.

Her stepfather's brother, Don Ayers, said he did not agree with how his brother and sister-in-law were portrayed.

"Thomas and Jennifer are being judged right now by what she is saying about them, but they aren't here to defend themselves because she killed them," he told People. "I think she stretched the truth to save her own neck."

Martinson told Crime Watch Daily that her hope is that one day her siblings can forgive her for what she's done.

"I hope that one day that they can come to me and I can tell them what really happened. The truth," she said. "Because I do want a relationship with them. I miss them so much. "