robert washburn's dna on jenni bastian's swimsuit.t was head-spinning. >> and the funny thing is he was not a high-priority suspect. >> he certainly had not acted like one. they learned after the murder and rape of jenni bastian, he moved to illinois, got a job, paid his taxes, stayed out of trouble. in fact, when investigators came knocking at his door, he voluntarily gave them a dna sample. now, more than three decades after that terrible day in the park, washburn was arrested at home. and then, the new cold case detective spoke with him. >> how did he react? >> he was scared. he was very nervous. he was sweating. he asked me, is this about that swab i gave the fbi a year ago? and then, he told me i didn't kill that little girl. >> reporter: with washburn in handcuffs, it was time to let jenni's mom know. and that job went to retired detective wade. >> so, of course, i had rehearsed what i was going to say. and it all went out the window by the time i got there. couldn't remember what i was going to say. >> and she walked in. i coul