. >> we know that rob render and brian carrick had an altercation because both their blood is at the scene. >> reporter: brian's blood in the hallway, rob's bloody fingerprint on the cooler door handle and inside the door more of rob render's blood. evidence kathleen says the state all but ignored at trial. when police asked rob why so much of his blood was found near the cooler -- >> cut my finger, who knows. maybe i bit my nail so bad that it bled a little bit. >> there's no way that this amount of blood could have been left by rob render biting his nails. >> reporter: for kathleen, there was motive. brian turned in rob for stealing booze, demanded monoed him for pot, and a new witness. >> what did this new witness say? >> said that remembereder had made a statement to him just a week before brian disappeared that he was very angry with brian and that he was going to jump him. with a weapon. >> reporter: that matched her version of events. kathleen said the fatal blow wasn't from a punch, as shane lam said, but from a knife. >> i believe that render comed up behind him like this and

the only person that owes money to brian carrick is render. the only person who's ever described wanting to jump him with a weapon is render. the only person in that back hallway is render. >> reporter: another bombshell. the state's star witness, shane lam, whose testimony put mario behind bars -- made a shocking about-face. >> all of it was false. every single thing. the state set it up. they said i'd be indicted for murder if i didn't cooperate. >> reporter: in a statement to abc news, the prosecutor's office denied coaching shane lam out of the presence of his lawyer, calling it unworthy of belief, untrue, and far-fetched. but shane's recantatation combined with confess evidence against mario amounted to a powerful appeal of mario's murder conviction. last week the appellate court of a panel of judges slammed the prosecution's case, calling their theory unreasonable, improbable, and unsatisfactory. two years into his 26-year sentence -- mario walked out of prison a free man. greeted by a busload of cheering family members and friends. >> h