we had boxes of files of dirt on robert missey.t what the defense didn't know was that prosecutors were putting up a straw man. missey wouldn't be their star witness at all. we were never going to use him in trial. our whole intent was to use him and have the defense running around, looking for him and everything they could find on him. dennis murphy (voiceover): and while the defense did just that, spinning its wheels, prosecutors were quietly working on reeling in another prize, another better witness, one clifford friend could only hope he'd never see again. craig melvin (voiceover): coming up, the other person on the boat that night breaks a promise and 20 years of silence. he said we have to dump the bag. craig melvin (voiceover): when "dateline" continues. billy: one second, grandma. this guy is going to buy my car. okay? grandma: you need carvana... entering plate number... grandma: no accidents, right? billy: no. grandma: generating offer... carvana can pick it up tomorrow! billy: that's an amazing offer. announcer: sell yo