A death row inmate used his last words as he was being executed to protest his innocence, declaring: I aint never took a life in my life.
Marion Wilson Jr., 42, was convicted of the 1996 shooting of off-duty prison guard Donovan Corey Parks, 24, southeast of Atlanta, Georgia.
He has spent the past two decades trying to prove his innocence, claiming it was another man, Robert Earl Butts Jr., who pulled the trigger.
Butts, 40, was also convicted of the killing and was executed in May last year.
Lawyers for Wilson tried to have his sentence commuted to life without parole before the execution, but their last-minute appeal was denied.
As he was tied to the gurney in the execution chamber Wilson turned to the witnesses and said: I aint never took a life in my life.
He also addressed his friends, family and supporters, saying: I love yall forever. Death cant stop it. Cant nothing stop it.
Wilson smiled and looked out at a woman sitting in the witness area and spoke to her, but the microphone had been turned off and it was difficult to hear what he was saying.
As the lethal drug pentobarbital was administered, he breathed deeply about 10 times, yawned and took several more deep breaths before becoming still.
He was pronounced dead at 9.52pm at the state prison in Jackson, Georgia.
According to the Atlanta Journal, for his final meal, Wilson ordered a medium thin-crust pizza with all the toppings, 20 buffalo wings, a pint of butter pecan ice cream, apple pie and grape juice.
Wilson is the 1,500th prisoner to be executed in the United States since the death penalty was reinstated in 1976.
Mr Parks was killed on March 28, 1996, after going to a Walmart to buy cat food and agreeing to give Wilson and Butts a lift in his car.
Prosecutors said the men ordered Parks out of the car, before shooting him in the back of the head and stealing his car, but never agreed who it was who pulled the trigger.
At Wilsons trial, while asking the jurors to impose the death penalty, District Attorney Fred Bright claimed Wilson blew (Parks) brains out on the side of the road.
During Butts trial a year later, Bright also claimed Butts pulled the trigger and blew out the brains of Donovan Corey Parks.
Lawyers for each man seized on that to argue that their client wasnt the triggerman and shouldnt be executed.