Former LAPD detective who murdered her ex-lover's wife and concealed crimes for decades remains behind bars

The former Los Angeles police officer convicted of murdering her ex-lover's wife in 2012 was denied parole Wednesday in the 1986 murder case and will continue to serve her 27-year sentence.

Stephanie Lazarus was convicted of murdering Sherri Rasmussen, a 29-year-old critical care manager at the hospital who was shot three times in the home she shared with her husband, John Ruetten.

Lazarus was sentenced to 27 years to life in prison after a jury found her guilty of first-degree murder. She was eligible for parole in 2023 after the state of California passed a law giving special consideration to juvenile offenders who committed their crimes when they were under 26 years old.

Lazarus was 25 years old at the time of the murder.

Commissioner Garland stated that the Board had found “good cause to revoke Lazarus' probation” and that it would reconvene for further hearings regarding Lazarus.

There will be another chance for parole. Lazarus will be scheduled for another fitness hearing within 120 days.

“The Killer Down the Hall,” a new “20/20” airing Friday, October 4, at 9 p.m. ET on ABC and streaming the next day on Hulu, tells the story of Stephanie Lazarus, including interviews with the victim's family and friends.

“It's definitely, um, pound for pound, one of the greatest true crime stories of all time,” Mark Groubert, a journalist who wrote an article about Lazarus' LAPD unit for LA Weekly, told 20/20.

Ruetten and Lazarus met at UCLA in the 1970s and had a friendly relationship that included casual sex, according to Ruetten's testimony in Lazarus' trial. Rütten also testified that he never considered Lazarus his girlfriend. He also admitted to sleeping with Lazarus shortly after his engagement to Rasmussen. On February 24, 1986, Ruetten discovered his wife in a pool of blood on the living room floor of their apartment in Van Nuys, California. He immediately called 911.

The original investigators determined that the crime scene at the home Ruetten and Rasmussen shared had all the signs of a “hot stalk,” a term police use to describe a home invasion. Investigators firmly believed that Rasmussen was the victim of a burglary that led to her murder. She had ligature marks on her wrist, indicating she had been bound at some point. She also had three gunshot wounds to the chest and a bite wound to her arm.

On the night of the murder, LAPD homicide detective Lyle Mayer questioned an emotional John Ruetten about what he knew about the day Sherri was killed.

Ruetten denied killing his wife and agreed to a polygraph examination, but the results were inconclusive. However, according to the Rasmussen family lawyer, he had a rock-solid alibi.

“He was at work that day,” said John Taylor, the attorney. “He had left work. He had stopped to pick up his laundry, then returned between 6pm and 7pm to find his wife murdered in the living room of the house.”

In the eyes of Mayer, the lead investigator, Ruetten was a grieving husband. Investigators said they didn't feel he was hiding anything and that they didn't think he was a suspect – and that's what they told him.

“I think your house was broken into today,” Mayer said to Rütten in the interrogation room. “When those individuals or that person or whoever was inside, I believe they tried to steal your stereo and probably some other items.”

Not long after Rasmussen's murder, investigators quickly pursued a new lead. Another burglary with a similar MO occurred in the same Van Nuys neighborhood.

When a woman came home, she interrupted the burglary and found two men in her home, one of whom was armed. They fled and witness sketches of the suspects were created. Although the LAPD had these new suspects, there was no evidence directly linking anyone to Rasmussen's murder. Sherri's family and friends believed the motive was personal. Her father, Nels Rasmussen, said he had asked police to investigate a disgruntled nurse Sherri worked with as well as Ruetten's former lover Stephanie Lazarus, whose name Rasmussen never knew. But investigators continued to focus solely on the burglary theory.

At this point, investigators said they did not have a single witness, fingerprints or murder weapon.

The case remained unsolved until 2001, when the Los Angeles Police Department established the LAPD's Cold Case Unit. This year, investigators were presented with more than 9,000 unsolved murders spanning more than two decades, and Rasmussen's case was one of them.

With new technology and new eyes, cold case investigators took another look at the bite mark found on Rasmussen's forearm.

Detective Cliff Shepard was the lead officer investigating the Rasmussen case for the unit.

“Up until that point, no one had really looked into it except Mayer and myself,” Shepard said. “When I went back through the reports, they indicated that a bite swab had been taken,” Shepard said. “And when I looked at the evidence… no evidence of a bite swab. So I checked with our accommodation, they confirmed that they hadn't booked the swab into our evidence collection. There is no record of it.”

Shepard enlisted the help of Jennifer Francis, a criminalist in the LAPD's Scientific Investigations Division, to find the swab, which she traced to a freezer in the LA County coroner's office.

The swab was sent to forensics for analysis, which produced a DNA profile of an unidentified woman, but did not show a match in law enforcement databases.

The DNA had given police a profile, but it did not provide a name. Despite this new information, the investigator's theory remained that Sherri's murderer or murderers were burglars. By 2005, Shepard had completed the Rasmussen Cold Case investigation without identifying a suspect, even with the DNA profile.

“My biggest regret is that I didn’t interview Rütten. “I haven’t met with him or had a personal conversation,” Shepard said.

The case remained dormant until 2009, when Detective Jim Nuttall of the Van Nuys department took over the investigation with fresh eyes.

One of the first things Nuttall noticed was Francis' four-year-old DNA report, which indicated that a woman was present at the murder. He also thought the stereo stacked near the door was suspicious, leading him to question the break-in theory.

After speaking again with Sherri's family and Ruetten, Nutall and his team of investigators compiled a list of five female suspects who were close to Rasmussen. Three of the five were immediately eliminated – Rasmussen's sister, mother and her close friend – after submitting DNA samples. The fourth suspect, a nurse with alleged tensions with Rasmussen at her workplace, was also eliminated.

The fifth suspect was Stephanie Lazarus, Ruetten's former college lover. Ruetten told Detective Nuttall that he had given Lazarus' name to the LAPD 23 years ago. However, the conversation was never documented.

Four months after the Rasmussen case was reopened, Nuttall did something no other officer investigating Sherri's murder had done: He took a hard look at Lazarus.

It was decided to have Lazarus tracked by a special surveillance unit to observe her and take a DNA sample. After following her, police noticed she had thrown a cup into a public trash can. They retrieved the cup to compare the DNA with that from the bite mark.

The DNA matched Rasmussen's bite mark and gave investigators the evidence they needed to arrest Lazarus. Lazarus was charged with Sherri's murder and pleaded not guilty.

In February 2012, 26 years after Rasmussen's murder, Lazarus stood trial at a courthouse in downtown Los Angeles. She was convicted of first-degree murder and sentenced to 25 years to life in prison and an additional two years for use of a firearm.

After her conviction, Lazarus continued to maintain her innocence, but changed her story in 2023 when she became eligible for parole.

“The only reason she confessed is because she wants to get out on parole,” said Teresa Marie Lane, a sister of Rasmussen. “We really need to keep her because she has no regard for what she did. She has no remorse.”