Grayson’s three accomplices managed to escape execution because they were under 18 at the time of Deblieux’s murder

The execution is the 22nd in the U.S. this year and the sixth in Alabama, which has put three of the men to death using nitrogen gas.

Prison officials in Alabama have executed convicted murderer Carey Dale Grayson, marking the state's sixth death sentence and third using the nitrogen gas method so far this year.