mike mcdaniel, david's first defense attorney, isn't buying that. >> i think he's a liar. >> you don'tt? >> no, i don't think he ever asked anybody to run it. >> he told you he did? >> yes. >> so when he says that the prosecution is lying. >> lying means that you knowingly -- you tell a falsehood. i didn't tell him a lie. i told him what i thought was true. >> reporter: what ever the truth is, now more than four years later, there was a name to that dna. >> do you allow yourself to think, here we are on our way to case closed, finally? >> absolutely. >> we've got a name -- >> sure. >> we've got genetic, forensic evidence. this is the shooter. >> right, that --. >> --this is the killer. >> absolutely. >> reporter: a new suspect in the hot seat. >> if anything else links you to it, you're done. stick a fork in you. >> you see, that would normally worry me. i wasn't there. >> this intense interrogation, where will it lead? feel the clarity of non-drowsy claritin and relief from symptoms caused by over 200 indoor and outdoor allergens. like those from buddy. because stuffed animals are cle