McALESTER, Okla. (AP) — Oklahoma has executed a man who stabbed a prison cafeteria worker to death in 1998 in the state’s first lethal injection following a six-year moratorium. Sixty-year-old John Marion Grant began convulsing and vomiting shortly after the first drug, midazolam, was administered. He was declared dead about 20 minutes after the execution began. Grant is the first inmate to be executed since a series of flawed executions in 2014 and 2015. Grant was serving a 130-year prison sentence for several armed robberies when witnesses say he dragged prison cafeteria worker Gay Carter into a mop closet and stabbed her 16 times with a homemade shank. Oklahoma moved forward with Grant’s lethal injection after the U.S. Supreme Court lifted stays of execution.