14 1/2-inch rolled gym mat opening to reach his shoe in the middle of a school day. they spoke with wolf blitzer moments after the announcement. >> i believe indeed that he was murdered. >> do you have any idea who may have murdered him? >> no, i don't. that's what we want to get down to the truth. >> the only question we want to know is why are they covering up for whoever killed their son. >> reporter: questions to the sheriff's department has made the johnson's suspicion, including why these shoes found yards from kendrick's body were not collected as evidence and how this bloodstain ended up on this wall in the gym and why investigators never found whose blood it was. and questions have also lingered about the state's autopsy. the official cause of death was positional asphyxia, kendrick was suffocated by his own body weight, but a second autopsy paid for by the johnson's found that kendrick died from blunt force