Witnesses watched through a window at an Alabama prison as Kenneth Eugene Smith became the nation's first person to be put to death using nitrogen gas.

ATMORE, Ala. (AP) — As witnesses including five news reporters watched through a window, Kenneth Eugene Smith, who was convicted and sentenced to die in the 1988 murder-for hire slaying of Elizabeth Sennett, convulsed on a gurney as Alabama carried out the nation’s first execution using nitrogen gas.