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