he was in the bathroom. he left his own dna in the bathroom. meredith may have come home and surprised him. maybe he was lying in wait. i hate to say it, but it's kind of the garden variety one guy kills -- tries to rape and rob girl case. >> in contrast to rudy guede's incriminating dna, amanda's defense team also set out to prove that the dna found on the knife, allegedly meredith's, did not implicate amanda or raffaele. >> they actually had independent experts come in, and they were absolutely appalled by the way the dna was collected and tested. >> those independent experts said the evidence is contaminated. it's not admissible. it's compromised. >> what they thought was meredith's dna was not dna at all. it was nothing. it didn't match her in any way, shape, or form. >> the prosecutor trying to rebut that suggests somehow amanda went back and cleaned up