How L.A. detective murdered ex-partner's new wife and managed to get away with it for 20 years

On February 24, 1986, the body of 29-year-old Sherri Rasmussen was found in the California home she shared with her husband, John Ruetten.

Sherri had been shot three times and beaten in a struggle, with police initially believing that the woman might have been killed in a burglary gone wrong.

The LAPD quickly ruled out Ruetten as a suspect, and Sherri's father, Nels, told officers that his daughter had been harassed by Stephanie Lazarus, a police officer and former partner of John Ruetten.

Lazarus had visited the couple in their home on the pretext of asking Ruetten to wax her skis, and Nels Rasmussen later said that the police officer visited his daughter to tell her: "If I can't have John, no one else will."

Ruetten had sex with Lazarus while he was engaged to Sherri 'to give her closure', which he later told a court was a 'mistake'.

Shortly before she was killed, Sherri told her dad she was worried that Lazarus was stalking her, but the investigation into her death stuck with the idea that it had been a burglary gone wrong, and the case went cold as no suspects could be found.

Stephanie Lazarus murdered her ex-partner's wife and got away with it for over 20 years (Ted Soqui/Corbis via Getty Images)

As the years went by, Lazarus ended up being promoted to the rank of detective in the LAPD, while forensic evidence and the way it could shed light on a case developed too.

A 2004 investigation into a saliva sample from a bite mark on Sherri Rasmussen's body did not produce a DNA match but did indicate that the 29-year-old had been bitten by a woman, which threw doubt on the burglary theory as most burglars are men.

That investigation flagged up that there had been a 'third-party female' who faced allegations of stalking and harassment against Sherri, which of course was Lazarus, but a detective said she was 'not a part of this' and with no other detectives picking up the case, it went cold again until 2009.

With the bite and likelihood that the suspect was a woman, the investigation started from the beginning on the assumption that a murder had been committed, finding that the signs pointing towards Rasmussen being killed during a burglary appeared to be staged.

Sherri's father Nels (left) told police about Lazarus, but for years they thought it was a burglary gone wrong (Jay L. Clendenin/Los Angeles Times via Getty Images)

Detectives drew up a list of five suspects, with Lazarus among them, and the investigation into the other women found they could be discounted as suspects.

The new investigation was then able to covertly collect a DNA sample from a cup Lazarus had been drinking from and found that it was a match for the sample taken from the bite mark on Sherri Rasmussen's body.

In July 2009, Lazarus was called in on the pretext that someone was in custody and wanted to talk about a theft since she'd have to give up her gun to get in, and when she arrived, she was told it was actually about Rasmussen's death.

She was then arrested, and in 2012, a jury convicted her of first-degree murder. She was then sentenced to 27 years in prison.

Lazarus later confessed to murdering Rasmussen at a parole hearing in 2023, with her parole initially being granted before California's governor Gavin Newson raised concerns that she had 'evaded justice for more than two decades and did not appear to begin taking full accountability for the murder until she was finally caught'.

Her parole was rescinded last year and she will next be eligible in 2028.