Outcry after Oklahoma prisoner vomits and convulses during execution

Witnesses describe gruesome scenes as John Grant, 60, put to death on Thursday in state's first judicial killing for six years

Oklahoma is coming under sharp criticism after witnesses to the state's first judicial killing for six years described gruesome scenes of the dying prisoner convulsing and vomiting as he was administered the lethal injections.

John Grant, 60, was pronounced dead at 4.21pm on Thursday at McAlester state penitentiary after he was injected with a triple cocktail of midazolam, vecuronium bromide and potassium chloride. Later, the department of corrections said the killing had gone in accordance with protocols and without complication".