In the decades after 29-year-old Sherri Rae Rasmussen was found bludgeoned and fatally shot in February 1986, her family never gave up hope of finding her killer. Los Angeles police believed

the nursing administrator died during a violent robbery and home invasion of the condo she shared with her new husband. But Rasmussen’s relatives suspected her spouse’s ex-girlfriend: LAPD

officer Stephanie Lazarus. Lazarus, Rasmussen’s parents said, had threatened Rasmussen at her workplace before she died, telling her, “If I can’t have John, nobody can.” How L.A. police

eventually traced the murder to one of their own is the focus of Monday night’s episode of _People Magazine Investigates_ on Investigation Discovery. An exclusive preview appears above.

BITTEN”_ _ON MON., DEC. 4, AT 10 P.M. ET ON INVESTIGATION DISCOVERY. _ “We were just getting into DNA, so our focus was sexual assault-type crimes or crimes where DNA evidence had been left

behind,” Detective Clifford Shephard, now retired, says in the exclusive preview clip. Lazarus was charged in Rasmussen’s death in 2009. During her 2012 trial, prosecutor Paul Nunez told

jurors that Lazarus’ “grief” as a scorned woman and her skills as a police officer provided the “perfect cocktail” for murder. Rasmussen’s husband, John Ruetten, tearfully testified at trial

that he had been friends and lovers with Lazarus since they were students together at UCLA. He said that after Lazarus heard of his engagement to Rasmussen, Lazarus invited him over and

told him she was still in love with him, and the two had sex. “The motive in this case was jealousy – jealousy toward Sherri,” Nunez argued. “The ring on Sherri’s finger was supposed to be

hers. It was ripped from her.” Lazarus was convicted of first-degree murder in March 2012. The state’s supreme court reportedly declined a defense request to review the case in 2015. _People

Magazine Investigates: Once Bitten_ airs Monday (10 p.m. ET) on Investigation Discovery.