She had a sworn duty to protect others. But her fellow police officers allege that one of their own -- a detective -- is a murderer who was involved in a love triangle more than two decades ago.
Los Angeles police Detective Stephanie Lazarus, 49, is being held without bail on charges that she killed Sherri Rasmussen in 1986 after Rasmussen married Lazarus' ex-boyfriend, John Ruetten.
While Lazarus has, for now, traded her badge for an orange jumpsuit, the attorney for Rasmussen's family said he was outraged that the LAPD did not investigate its detective for 23 years and accused the department of ignoring vital clues from Rasmussen's parents.
"They provided information on the first day and at the first interview indicating that Stephanie Lazarus was a suspect in this murder," John Taylor said on the courthouse steps recently, adding that Rasmussen had told her parents that Lazarus had threatened her at the hospital where she worked.
"If I cannot have John, nobody can," Taylor said, reciting Rasmussen's words.
Rasmussen's father, Nels Rasmussen, has alleged that when he brought his concerns to the LAPD, he was told he was "watching too much TV." Police had investigated the murder as stemming from a burglary even though the only things taken from the house were the couple's marriage certificate and Rasmussen's car, which was found a short time later.
Rasmussen was badly beaten and had been shot three times, including in the heart and spine.
Her murder went unsolved and was filed as a cold case until new DNA technology showed saliva that was found on Rasmussen's body came from a woman.
The LAPD secretly took an eating utensil that Lazarus had used and tested it. It was a perfect match, and she was arrested Friday.
Police said she was on the third floor of police headquarters with a weapon on her hip when she was given a routine request to report to the jail to talk to a suspect. It was, police said, a trap to arrest her.
Now she could face the death penalty.
Nels Rasmussen said in a recent radio interview that he is grateful for Lazarus' arrest. "She was just a person that cared and it showed," he said of his daughter.
Legal experts say Lazarus' arrest shows much has changed in the LAPD in the 23 years since Rasmussen was murdered.
"It used to be, 'Protect your own, cops can do no wrong,'" legal expert Dana Cole told "Good Morning America" today.
Police in Los Angeles have said that the city's 32 percent drop in homicides has allowed the LAPD to spend more time solving cold cases such as Rasmussen's.
The Associated Press contributed to this story.