one made public when former district attorney mary lacey exonerated the ramsey family in 2008. saying there's no innocent explanation for genetic material found on the girls underwear and longjohns. >> my guess is that if we took your shirt and did some dna testing on it at the level of sensitivity in this case we well. >> reporter: the exoneration letter said she concluded foreign dna on jonbenet's clothing could not have gotten there inadvertently. something our experts say is just not true. they say there are plenty of reasons the dna on jonbenet's clothing could be innocent. reasons that have nothing to do with murder. >> you shed 40,000 cells per hour. you are leaving your dna everywhere. wherever you go physically. leaving it discounted that possibility when she issued her letter examined dating the ramseys and concluded the dna must be the killer's. >> that was a leap to claim that there couldn't be an innocent explanation for what was found. >> reporter: how did lacey's conclusion differ so much? lacey was long known to support the theory that an intruder not a family m