tony frudakis called investigators with a warning that eyewitnesses and behavioral profiles are not alwaysight. >> that type of information is oftentimes wrong. sometimes people lie. sometimes they're just flat out mistaken. >> so dr. frudakis made the police an offer. he said he'd perform a new dna test and promised he could identify the killer's physical characteristics. >> to be honest with you, i didn't really believe. i thought he must be a quack. how can he do this? but he purported he can determine the race of folks from dna, and i said, there is no way in the world he can do that. >> this new test called dna witness ascertains the exact ancestry of an individual based on information in their dna. it's rooted in the fact that all humans are descended from a common gene pool. >> so, instead of measuring the pigmentation genes that control pigmentation of the skin, we can make an indirect inference about your skin shade through a very precise knowledge of your ancestral background. >> so the baton rouge police gave dr. frudakis the go ahead. the results made forensic history and chang