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Rachel Mullenix and Ian Allen, of Huntington Beach, California, fancied themselves star-crossed lovers when they fell in together in 2006. Mullenix, 17, had moved to the beach community a year before with her parents, Barbara and Bruce, from Oklahoma. The parents had recently divorced, but were living together while Barbara tried to get on her feet financially.
Bruce and Barbara had given a grudging OK to underage Rachel’s relationship with the 21-year-old Allen; they even provided Rachel’s older beau with a signed note indicating that they assented to the relationship. But as the young couple started spending more and more time together, Barbara tried to tighten the leash on her daughter, according to “Killer Couples” on Oxygen.
Rachel began to believe that drastic measures had to be taken if she were to stay with her Romeo.
On Sept. 13 of that year, Barbara’s horribly brutalized body would be found floating in the water by the Newport Harbor Yacht Club. She was wrapped in a sheet and had a butter knife sticking out of an eye socket; almost the entire blade was embedded deep in her skull.
“My breath was taken away by the brutality,” Newport Beach Detective Sgt. David Byington told “Killer Couples” producers. “It was obvious that this murder was vicious.”
Investigators didn’t have an ID for the body at first, let alone a suspect. However, the 56-year-old woman’s breast implants and their serial number finally got them a name. They headed to the condo she shared with Bruce and Rachel, figuring the best place to start would be with her husband.
No one was at the apartment, but police saw enough to guess that the woman had almost surely been murdered there. Although a clean-up had obviously been attempted, bloodstains were still visible in the bedroom. Also, the kitchen was stocked with the very same kind of knife that was found sticking out of Barbara’s eye. Immediately, Bruce became the top suspect.
There was no sign of Bruce or his daughter, however. That is, until Bruce himself walked up to a detective standing outside and introduced himself — he wanted to know why his home was suddenly a crime scene.
Bruce behaved oddly when told that his ex-wife was dead, authorities told “Killer Couples.” When officers told him, he remained “stone-faced” until he was informed that Rachel was also missing. Then, he came alive with concern.
Still, he was their prime suspect at the moment, and he was brought to the station while detectives executed a search warrant on his car. They found nothing and Bruce’s alibi — he was at a business trip in Fresno at the time of the murder — checked out.
Investigators’ next task was finding Rachel — and Allen, who Bruce had filled them in on. Detectives worried that the girl’s older boyfriend could be the murderer and Rachel could be being held against her will or worse. Authorities put out a nationwide all-points bulletin, which yielded a sighting in Louisiana.
When local law enforcement pulled over Allen’s truck, Rachel ran screaming from it, detectives told “Killer Couples.” When both the lovers were in custody and separated, Rachel told detectives a story they didn’t quite believe, about her boyfriend murdering her mother and kidnapping her.
Investigators had already seen surveillance footage from inside a convenience store shortly after Barbara was likely murdered, and Rachel was not acting like an abductee. She appeared to be moving about freely, and investigators observed plenty of opportunities for her to escape, were she being held hostage. She acted like Allen’s girlfriend.
Police interview footage obtained by “Killer Couples” shows Rachel’s performance start to break down when investigators push back on her story.
“I didn’t kill my mom. I want my mom,” she tearfully repeats.
Meanwhile, in another interview room, Allen was ready to come clean.
“He felt genuine remorse,” Byington said, recalling how Allen painted investigators a very different picture of his relationship with Rachel.
Allen told investigators that Rachel fed him false stories about her mother abusing her and warned him that Barbara was going to get him fired somehow. Soon, Barbara did indeed threaten to call the police if Allen didn’t leave her daughter alone. Then, Rachel found herself grounded for missing her 1 a.m. curfew, according to the Los Angeles Times. That was the last straw, according to Allen, prompting Rachel’s plan to run away.
“I lost it,” he told investigators, telling them that he took Rachel’s advice that the only way to fix the situation was to kill Barbara. That night, Allen entered the Mullenix home through the back door, he told investigators. He grabbed two knives from the kitchen and was shaking so badly that it took him an hour to make it upstairs to Barbara’s bedroom.
There, the two attacked Barbara together, prosecutors alleged, stabbing her 52 times. Allen horrifyingly described to investigators how he intended the butter-knife wound to be a killing blow, but it only made Barbara scream louder.
The way the knife slid under Barbara’s eyeball and into her skull would have caused “excruciating pain,” authorities told “Killer Couples.”
Allen tried to minimize Rachel’s involvement in his confession, but when the case went to trial, prosecutors painted her as the clear mastermind of the killing.
Prosecutor Sonia Balleste called Rachel a sociopath, who she believed wasn’t “capable of feeling anything at all,” the Los Angeles Times reported.
After four days of deliberations, a jury convicted her and sentenced her to 25 years to life. Allen was later also convicted of first-degree murder and received the same sentence.
Rachel filed an appeal of her conviction in 2010, alleging prosecutorial misconduct, but the conviction was upheld, according to court documents.
For more on the deadly romance of Rachel Mullenix and Ian Allen, watch “Killer Couples,” airing Thursdays at 8/7c on Oxygen.
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