A US death row prisoner has been executed despite a last-minute plea that an execution drug bought from a pharmacy could cause inhuman suffering.

Michael Taylor, 47, was pronounced dead at Missouri state prison in Bonne Terre. Federal courts and the state governor had refused last-minute appeals from his lawyers over the execution drug.

Taylor offered no final statement. He mouthed silent words to his parents, two clergymen and other relatives who witnessed his death. He took two deep breaths before closing his eyes for the last time.

Loading article content

His death was the state's fourth execution by lethal injection in as many months.

Taylor was sentenced to death for abducting, raping and killing a Kansas City teenager as she waited for her school bus in 1989.

His lawyers had questioned Missouri's use of an unnamed pharmacy to provide the execution drug Pentobarbital.

But state officials said the drug had been used in three previous executions and none of the inmates showed signs of distress.