Clayton Lockett , 1999 , shot and buried alive Stephanie Neiman , 19 , in 38 . Prisoner was killed in 'horror movie-style ' botched execution last spring . New documents have revealed he chatted with Oklahoma prison guards . Even suggested a vein for lethal injection after medic could not find one . Untested cocktail of 3 drugs ultimately leaked into Lockett 's body tissue . Execution described as a 'bloody mess ' ; prisoner took 43 minutes to die .
Clayton Lockett , 38 , shot and buried alive Stephanie Neiman , 19 , in 1999 . Prisoner was killed in 'horror movie-style ' botched execution last spring . New documents have revealed he chatted with Oklahoma prison guards . Even suggested a vein for lethal injection after medic could not find one . Untested cocktail of 3 drugs ultimately leaked into Lockett 's body tissue . Execution described as a 'bloody mess ' ; prisoner took 43 minutes to die .