. >> reporter: greg hampikian is a forensic biologist at boise state university and director of idaho'snnocence project. he also is working with the knox defense team. he says italian investigators did a good job processing the crime scene, collected excellent evidence, but clung to shakier evidence that proved their theory. a classic error, says he, a prosecutor who trusted his gut feeling instead of the science that at that time was pointing to another suspect. >> when the dna's finally processed, it's not any of their suspects. so what do you do? what would you do? you let them go. >> as patrick lamumba was being released from jail, investigators analyzing the bloody evidence left at the crime scene found an entirely new suspect. his name? rudy guday, a known petty criminal from the ivory coast who fled to germany shortly after the murder. it turns out guday's handprint made in meredith kercher's own blood was found in the victim's room. his dna found inside the victim's body in her vagina. his dna on her clothing, on her purse. his feces even found on used toilet paper left near an