Police said that Christopher Paul Mason kidnapped and killed Joshua Calkins, a fellow resident of Phoenix and alleged member of the same white supremacist prison gang, according to the Arizona Republic. Television station KPNX reported both were part of the Aryan Brotherhood.
Calkins was killed in April in a near-decapitation that a medical examiner said was most likely a brutal ax-murder.
According to records cited by the Republic, Mason confessed the killing to a confidant, saying, "I got him 13 times with an ax." Court documents reportedly show Mason asked another witness to help him clean up the killing with bleach.
Mason told other witnesses that he killed Calkins in revenge, after his victim mugged his former girlfriend at gunpoint, the paper reported.