that mattered, july 13th and 14th, 1990, renaud had to admit he just didn't remember. >> you could have used it, or you could not have used it. you don't remember. >> correct. >> again, the defense's goal was to raise reasonable doubt about renaud's recall and credibility. >> marijuana can cause a time distortion, so we're talking to a person that does not have the best handle on time. >> now that the defense believed it had shredded renaud's story, it was ready to tell the jury who really murdered barbara george. coming up -- >> another possible suspect in an impossibly strange disguise. >> he said it looked like a woman in a fake beard, a really thin guy. womanly hips or something. >> when "dateline" don'ts. >> when "dateline" don'ts.