Produced by Chuck Stevenson, Jenna Jackson, Anthony Venditti and James Stolz
(This story originally aired March 20, 2010. It was updated on Dec. 18.)
In the summer of 2005, police were called to an apartment in Austin, Texas. Inside, a woman's body lay in the bathtub; her hands and head severed. Police would soon learn the butchered victim was 21-year-old Jennifer Cave.
For Travis County Prosecutor Bill Bishop, the case is indelible.
"As far as murders go, this is a very clean murder. He shot her through the arm, bullet traveled into the chest, through the heart pretty much killing her instantly. It was the post-murder behavior that made it so grotesque.
"The mutilation was anger... it wasn't any effort to hide the body or get rid of the body. It was just playing with it, like it was toy," Bishop tells "48 Hours Mystery" correspondent Maureen Maher.
The apartment belonged to Colton Pitonyak, a University of Texas business student. But Colton was nowhere to be found.
"The kitchen I think was the oddest room to me because it was sparkling clean," Bishop tells Maher.
"Really? A boy's dorm room was sparkling clean? His kitchen?" Maher asks in disbelief.
"Even looked like the floors had been mopped. They found a machete that was in the dishwasher."
Police urgently needed to know everything about Colton and Jennifer.
"I have never heard anyone say anything but that she was one of the nicest people they knew," Bishop says of Jennifer.
But as the investigation grew, the most intriguing player would be Laura Hall.
"In your mind you're 100 percent convinced that Laura Hall was absolutely a part of the dismemberment and mutilation?" Maher asks.
"I believe she was," Bishop replies.
"48 Hours" has been following Laura Hall's case since 2005, and yet it is still difficult to know just exactly who Laura is or what role she played that awful August night in Austin. The events are so hard to believe. And many say, so is Laura.
As Laura tells it, she had nothing to do with the horrific crime. But she admits she is guilty of falling in love with the wrong man. "Oh, I loved the guy," she says. "I loved Colton Pitonyak."
Laura and Colton met at a party in the spring of 2005. She was also a student at UT, a government major with hopes of becoming a lawyer.
"I was really attracted to Colton from the beginning. I thought he was a very sexy guy. He was hot. We immediately just got together. Right away. It was great," she says smiling. "We would spend days together at a time. We'd just stay in the house all day. Yeah," she continues with a laugh, "I felt I was on top of the world when I was with Colton."
"Until you get to know Colton," she continues, "you can't see on the surface that there's something wrong underneath."
So without knowing anything was wrong, Laura says she showed up at Colton's apartment just before dawn on Aug. 17, 2005. He'd called her saying he needed to talk.
"He answered the door really kind of paranoid and fearful. And I'm kind of like, sitting up, 'Colton, what's the deal, what's going on?' I'm kind of starting to freak out a little bit. And he says, 'Come here. Come here.'"
Laura says Colton led her into the bathroom.
"There was a dead woman curled up in his bathtub. And I said. 'That's a mannequin.' I mean, that's how much I did not believe or wanna believe... I was like, 'Man, oh my God, you know, 'What happened?'"
Laura says Colton had been drinking and says he didn't remember what had happened.
"I remember him goading me out of the bathroom with a knife that had blood on it up to the hilt... The last thing you wanna think is this person that I've had sex with has, you know, killed somebody. So you kind of want to know, who came in here and did this? And the other thing you kind of think is, 'Well, there's one. Am I next?'"
But then, surprisingly, Laura says Colton just let her go.
Laura says she went home. "I mean I still - I was in denial, OK."
Asked if it never occurred to her to call police, family or friends, Laura says, somewhat defensively, "It didn't seem like a good move. I mean, look, I didn't know what was gonna happen if I called the police, OK? There was nothing I could have done to save her life at that point."
Maher asks, "Did you have any concern for the girl who was dead?"
Laura sighs before answering. "I wasn't able to even process - and even today, I have not processed the emotions. I didn't know who she was."