Alabama executes man on death row by controversial nitrogen gas method

Anthony Boyd, 54, says I didn't kill anybody' as Justice Sonya Sotomayor writes excoriating dissenting opinion

An Alabama man convicted of helping to burn a man alive was executed by nitrogen gas - a form of suffocation which defense lawyers have described as cruel and unusual punishment - on Thursday shortly after the US supreme court signed off on the seventh execution using the contested method.

Anthony Boyd, 54, was sent to the death chamber at the William C Holman correctional facility on Thursday evening.