As a prosecutor, he prosecuted a famous cold case in 2012 and won a murder conviction against a veteran LAPD police detective named Stephanie Lazarus. In 1986, Lazarus shot and killed her ex-boyfriend's wife out of jealousy. There were no eyewitnesses and DNA testing wasn't conducted then, even though a swab was taken, capturing saliva from a bite mark on victim's body. The LAPD didn't consider Lazarus a suspect at the time, and she advanced in her career from patrol officer to detective. In 2009, detectives from her own police force reopened the cold case and arrested Lazarus, after DNA testing of the swab showed that it was her. Her arrest and conviction made news, and Presby, as prosecutor, gained exposure on several news programs.