he contacted john ruetten, sherri's former husband, now remarried and living in san diego. >> john explainedinvolved in a relationship with stephanie lazarus. >> stephanie lazarus. that was the other name still on the short list of suspects. he pressed ruetten for more when it started when they were both students at uclla. >> but you're convinced the relationship that john had with stephanie lazarus was overlapped with the relationship he had with his wife? >> we know from john there was at least on one occasion when he was engaged that he was intimate with stephanie lazarus. there was a love triangle. stephanie lazarus had deep feelings for john ruetten, and may have had a motive to hunt sherri rasmussen. >> was her killer a scorned lover or a jealous coworker? >> we had two women on the list who in our opinion had a motive to harmer had. deborah, a nurse, and stephanie husband russian? >> correct. >> reporter: cops tracked down deborah and secretly scooped up a sample of her trash, which contained dna. it was sent to the crime lab in l.a. for analysis. 72 hours later came an answer. >> she