cops tracked down debra and secretly scooped up a sample of her trash which contained dna. it was sent to the crime lab in l.a. for analysis and 72 hours later, came an answer. she was not the donor of the dna profile from the bite. reporter: that left just one possible suspect, number five on the list, john ruetten s ex-girlfriend stephanie lazarus. nutall called the rasmussens. we came home and there was a message on our phone from a detective that they wanted to talk to us. i thought oh, yeah, right. i thought it was just another false hope. reporter: this is detective nutall? right. he said that they were opening the investigation. nells was upset with me. it was like detective where have you been for the last two decades. reporter: now nells rasmussen explained it all. how he told detectives back in 1986 that someone was stalking his daughter sherri, a woman
evidence. you can t rely on the scientific results. reporter: overland said hair, blood, fingerprints found at the crime scene did not come from lazarus. the shots that were fired? he insisted several other types of guns besides stephanie that could have fired those bullets. as for motive? the defense argued there was no evidence that stephanie lazarus was object sessessed with sherr husband john. john was still calling her and stephanie went to tell sherri, look, you guys are getting married, i m telling him not to call me. reporter: after five weeks, it was up to the jury. loretta and nells rasmussen had waited a long longer than that. the two of you feel confident? as confident as you can be with a jury. you never know what is jury is
with crazy eyes, the ex-girlfriend of sherri s husband. nells had never known that the girlfriend s name was stephanie lazarus. but he did know something else about her. something very important and by this time, detective nutall knew it too. he was very cautious of what he said. but he said that we would be hearing more from him. reporter: nutall had ample reason to be cautious. because he learned that stephanie lazarus wore the same badge he did. we now have a los angeles police officer as a person of interest in a murder case. reporter: and you thought i ve bitten off more than i can chew? toto, we are not in kansas any more. that changed everything. reporter: coming up, a top secret investigation, as detectives go after one of their own. we would never leave a paper trail of what we were doing. she worked our unit. reporter: when dateline continues. unit. reporter: when dateline continues.
scooped up a sample of her trash that contained dna. it was sent to the crime lab in l.a. for analysis. and 72 hours later, came an answer. she was not the donor of the dna profile from the bite. reporter: that left one possible suspect, number five on the list. john rutten s ex-girlfriend, stephanie lazarus. he called the rasmussens. we came home and there was a message that there was a detective that wanted to talk to us, and i thought, oh, yeah, right. i thought it was another false hope. reporter: this is detective nutall. he said that they were opening the investigation. they were upset with me, it was like, detective, where have you been for the last two dec e decaddecade s. reporter: and now, nells rasmussen explained it all saying that someone was stalking his daughter sherry, a woman