Investigators are looking into whether a white supremacist prison gang is responsible for at least nine mysterious disappearances in Oklahoma, The Oklahoman reported Friday. The state's chief medical examiner, Dr. Eric Pfeifer, told the outlet earlier this week that the “list keeps growing” of missing people, with other sources telling the paper that 12 people have in fact vanished. “We haven't sifted all the material,” Pfeifer said following the discovery of human remains at separate two locations. “We brought back over 500 pounds of dirt to the office. And they are going through all of it with a fine sieve. But the thinking is, when they were out there in the field … is that they may have found bones of three individuals… They were associated with burned wood and other material. … We’ve got our work cut out for us.” Universal Aryan Brotherhood leader Mikell Patrick “Bulldog” Smith, who is serving a life sentence for murdering a schoolteacher in 1985, owns the land where the first set of remains was found, sources told The Oklahoman.