LAS VEGAS (KLAS) — How does a teenager wind up committing a brutal murder?

Aaron Guerrero, 20, revealed what happened in the moments leading up to the murder of his girlfriend’s father in an interview with 8 News Now Investigator Vanessa Murphy.

Daniel Halseth, 45, was stabbed 70 times and his body was found dismembered and burned in April 2021. The killers were his own 16-year-old daughter, Sierra, and then-18-year-old Guerrero, who was her boyfriend at the time.

“She got the weapon first and I always carry a weapon, so you know that’s what led to what happened after that,” Guerrero said

Daniel Halseth. (KLAS)

“Whose idea was it to commit the murder?” Murphy asked.

“Well, I would say it was both of our ideas because we didn’t know exactly what we were going to do, but we knew we had to do something about it and it turned out terribly wrong,” Guerrero replied.

The teens claimed that Halseth abused and mistreated his daughter, while his family said this is completely false.

After the murder, the teens stole Halseth’s car and were later captured in Salt Lake City, shortly after recording a video of themselves saying they had killed someone.

In the video, Guerrero was seen saying “day three after murdering somebody” before Sierra replied not to say that on camera.

“We were both trying to cope with what happened and we, I can’t say for Sierra, but personally I feel guilt every day,” Guerrero said.

At the sentencing in October, Sierra offered no apology, while Guerrero did. Both teens pleaded guilty to murder and were sentenced to life with the possibility of parole after 22 years.

Sierra Halseth and Aaron Guerrero appear in court for their sentencing on Oct. 20, 2022. (KLAS)

Guerrero agreed to speak with 8 News Now from jail the day after learning his fate and before he would be sent to maximum security High Desert State Prison.

Guerrero said he hadn’t been in much trouble previously, had suffered from mental health issues, and wasn’t taking his medication.

“I would pretend like I would take it and I feel like that has some form or impact in what happened,” he said.

He also claims he was using LSD, which he said he ordered through a website he didn’t want to name.

Evidence presented to a grand jury in the Daniel Halseth murder case. (KLAS)

“I don’t think I would have been capable of something like that had I been sober, because it’s a psychological drug as most people know, and when you have a mental illness it only makes it worse,” he said.

Today, Guerrero said he is taking the medication he needs, and that if he is ever granted parole, he hopes to show the Halseth family he is a better person.

“How are you going to make it up to them?” Murphy asked.

“By proving to them that I’m not a monster, that I still have potential to be a functioning member of society and can benefit society,” he replied.

Evidence presented to a grand jury in the Daniel Halseth murder case. (KLAS)

Sierra Halseth is currently at the Florence McClure Women’s Correctional Center in North Las Vegas. Guerrero said he plans on having no contact with her.

“I think I acted more out of impulse than what you could call love,” he said,

Sierra is the daughter of former Republican state lawmaker Elizabeth Halseth. She and Daniel had a public battle as their relationship fell apart, and a custody battle over their children followed.