When detectives explore a cold case murder, they are surprised to learn what the DNA left behind can tell them. In the latest episode of Oxygen True Crime, Real Murders of Los Angeles, detectives recall the cold case murder of Sherri Rasmussen, a nurse administrator who was found dead in her apartment with bite marks on her arm.

Sherri was murdered in what police thought was a botched break-in, likely done by two males. In an exclusive clip shared with Showbiz Cheat Sheet, retired detective Cliff Shepard recalled digging back into the cold case in 2001.

The 1986 murder of Sherri Rasmussen appeared to be something they could hopefully solve because DNA from bite marks was left on the victim’s arm.

“Our emphasis was on DNA cases,” he explained. “Because DNA was new to us. We were learning what to do with it.”

“I read the Sherri Rasmussen case and I read that detectives were working on a theory that she’s home. Burglars come in and she surprises them,” Shepard continued. “And Sherri had been bitten on the arm during the fight.”

“Supposedly we’re looking for two males,” he added. “Possibly the same that were seen burglarizing another location a few weeks later.”

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The L.A. bite mark killer shocked detectives

According to investigators, bite marks are “rich sources of DNA.” A bite swab had been taken. “The DNA on the bite swab could identify them,” Shepard said. “If anything’s going to solve this case, it’s going to be DNA.”

Shepard hopes that whoever bit Sherri will be a listed offender in a criminal DNA database.

What detectives found during that 2001 investigation is nothing short of shocking. Police ultimately uncovered the killer and it was literally the last person they could have considered.

So how did detectives finally crack the 23-year-old case? And what was the motive behind the murder?

When is the new episode of ‘Real Murders of Los Angeles’ on?

Narrated by Real Housewives of Beverly Hills star Garcelle Beauvais, the series premieres new episodes on Fridays at 9 pm ET/PT.

In the City of Angels, as everyone strives for the unattainable high life, there are some who are willing to kill to get it. Oxygen True Crime expands its “Real Murders” franchise to Los Angeles as it looks beyond the city’s glamorous façade to expose a dark underbelly where the pursuit of the American Dream can turn deadly.