The Teenage Love Triangle Killers: Inside Their Lives Now

This case was featured on Monday night’s People Magazine Investigates. Learn more with PEOPLE’s complete digital coverage.

David Graham and Diane Zamora were only teenagers when they were arrested for a brutal crime: the beating and shooting death of 16-year-old Adrianne Jones, a well-like girl in Mansfield, Texas, who fell between Graham and Zamora with deadly consequences.

Graham and Zamora were convicted of Adrianne’s murder in the ’90s and have spent two decades behind bars — where they will remain at least until they are eligible for parole in 2036. Their arrests and conviction were featured on Monday night’s episode of People Magazine Investigates, on Investigation Discovery.

In their years in prison, the formerly inseparable couple, who were engaged before their murder arrests and later split, have had some similar experiences. Here’s a look at their lives now.

David Graham

In an early 2008 interview, Graham — like Zamora did before him and would do after him — struck a publicly remorseful tone about Adrianne’s December 1995.

“I wish I had’ve pled guilty from day one,” he told the Dallas Morning News. “If I had it to do over, I’d plead guilty to murder and let a judge sentence me and that’s it.” And, like Zamora, Graham blamed the driving force for the murder on the other person involved — in this case, her.

“She was the motivator, but I went through with it and that’s all that really matters,” he said.

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Adrianne JonesKEATON DOYLE/CORBIS/Getty

“Regrets? I start with the simple fact of killing Adrianne and everything that surrounded that,” Graham said. “I don’t see the two of us being any different in our culpability. ”

In 2010, he said he had gotten married. Earlier that year, he started a blog from prison with a fellow inmate called Prison News Exposed and he “plan to debate prison issues,” according to the Morning News. Without access to the Internet, Graham said he posted to the site via mail to a third party.

Graham also said he earned a bachelor’s degree in criminology.

And while he has previously recanted his confession, which was the centerpiece of the prosecution against him, he told the Morning News it was accurate: “I’m not going to tell people who love Adrianne that we don’t deserve life in prison.”

From left: David Graham and Diane Zamora in 1996.Fort Worth Star-Telegram/Robert J. Ruiz/AP

Diane Zamora

Like Graham, Zamora wed in prison: She married inmate Steven Mora in 2003. She was also featured in a 2007 episode of NBC’s Dateline, where she went public for the first time from prison with her claims of innocence.

“I’m not a killer and that I’m not some witch,” she said then. “I’m not some evil-hearted person, not even close.”

Her comments to Dateline echo what she tells People Magazine Investigates in Monday night’s episode on the Adrianne Jones murder: That she witnessed the girl’s death, and helped hide it, but did not help kill her. (Graham could not immediately be reached by PEOPLE.)

“I think I remember seeing one time, just noticing her,” Zamora says on PMI‘s upcoming episode. “I have a vague recollection, but I’d never heard her name, anything about her. I’d never seen a picture. … I didn’t know anything of her at all.”

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“It wasn’t her fault, but she wouldn’t have been in that position had I not lost my temper,” Zamora says.

She says she is no longer in contact with Graham, either: He reportedly sent her a Christmas in 2001, to no avail.

Adrianne’s family, meanwhile has kept private since her killers were convicted. They have not forgotten their daughter, and have asked the same of others.

“The end of this day is not the end of my life or our family’s life,” Adrianne’s mother said as Graham and Zamora were convicted. “But I hope that everyone remembers our daughter with the integrity that she has — ’cause she’e still among us, watching us. I remember her eyes with joy.”

People Magazine Investigates airs Mondays (1o p.m. ET) on Investigation Discovery.