Produced by Ira Sutow and Allen Alter
This story originally aired Jan. 24, 2009. It was updated on June 6.
On Sept. 13, 2006, police in the upscale community of Newport Beach, Calif., were called to the Newport Harbor Yacht Club after a report of a body in the water. The victim, a woman, had been brutally murdered, stabbed 52 times.
Identifying the victim was no easy task - investigators had to resort to using serial numbers found on her breast implants to come up with a name: Barbara Mullenix, age 56.
Why would somebody want Barbara dead?
Nineteen-year-old Rachael Mullenix lights up when she recalls her childhood. "I had a lot of fun with my mom. She had a wild and free spirit, fun to be around," she tells 48 Hours Mystery correspondent Erin Moriarty. "I was spoiled. I was. It was like Disneyland. My life was really, really, really good."
The only child of Bruce and Barbara Mullenix, Rachael says she always felt a special connection to her mom. "We were closer than most mothers and daughters."
It was Barbara's outgoing personality that had caught the attention of Bruce back in the mid 1980s. "She was very opinionated. She wasn't afraid to tell somebody what she thought. To me, that was attractive. It was different. You know, I kind of liked it," he remembers. "I was taken by her."
The couple married in November 1987. Bruce was nearly 28 at the time. Barbara was nine-and-a-half years older. It was her third marriage; her first two had failed. The couple were living in Oklahoma City, Okla., and within a short time they had Rachael.
Bruce says the marriage began to crumble when Barbara began drinking more heavily. "Barbara had a problem," he says. "When she got more and more into the drinking, things started to get bad."
The couple divorced in 2002. Bruce moved to California, free of Barbara - or so he thought. "The alimony and the child support my dad was giving her was not enough to support herself," Rachael says.
So in 2005, three years after the divorce and against his better judgment, Bruce helped his ex-wife and daughter move cross-country and into his small apartment.
Bruce acknowledges it was a bad living situation. But it wasn't all bad: they were living near Hollywood, and Barbara was star struck. She soon found part-time work as an extra in Hollywood movies and TV shows. She landed small roles in shows like "CSI."
Whoever murdered Barbara not only stabbed her dozens of times, they also dumped her body in a taped-up cardboard box, which had fallen apart in Newport Harbor.
Once the victim was identified, Detectives Steve Mack and Joe Cartwright were wondering why no one had reported her missing. They were eager to get over to Bruce and Barbara's Huntington Beach apartment.
"She was wrapped in bedding. It appeared to me that she had been killed on a bed and simply wrapped up in those sheets," Cartwright remembers.
No one was home when police arrived, but detectives got a search warrant and went in. "There was nothing immediately noticed when you walked in," Mack remembers.
But they did find something strange in an upstairs bedroom: a collapsed bed frame with no bed, and on closer inspection, some blood spatter on a wall that Mack says was ultimately discovered by the forensic lab.
Detectives realized that someone had tried hard to clean up the scene in that room. "I think that the reason that the mattress and the box spring were missing is because they were saturated in blood," Mack says.
Police were now convinced that the apartment is where Barbara was murdered. That fact, and the ferociousness of the attack, helped confirm for detectives that this was no random killing and that Barbara knew her assailant.
Attention immediately focused on Bruce. "No, I understand. I'm the ex-husband. We're living in the same condo," he tells Moriarty. "I have watched crime shows. I've watched '48 Hours.' …The ex is usually the first person you go to."
The detectives urgently wanted to speak with Bruce, but as far as they knew, he was missing, which made them even more suspicious.
But one day after Barbara's body was discovered, Bruce did show up at the condo, telling detectives that he'd been out of town on business and that he became worried when he couldn't reach Barbara or Rachael.
And so he says he rushed home, only to be horrified at what he discovered.
But Steve Mack, the lead detective, says Bruce reacted calmly when told his ex-wife had been murdered. Too calmly.