Arkansas has put to death its fourth inmate within a week after a dozen years without a single execution.
Kenneth Williams, 38, killed two people after escaping from a maximum-security prison where he was serving life for murdering a cheerleader.
His lawyers said he was intellectually disabled, but the US Supreme Court rejected his last appeal.
The four executions were carried out before the state's supply of a drug used in lethal injections could expire.
Williams was pronounced dead at 23:05 (04:05 GMT Friday), after briefly coughing and convulsing, witnesses said.
Convicted murderer
was first to be put to death last Thursday.
The next two,
, were executed on Monday.
Four other death row inmates won reprieves.
State prosecutors have vowed to appeal and put them to death as well.
Williams was sentenced to life in prison for the 1998 murder of 19-year-old cheerleader Dominique Hurd. A jury had spared him the death penalty.
After a month in the penitentiary, he escaped on 3 October 1999 by hiding in a barrel used to carry kitchen refuse.
Not far from the prison, he encountered Cecil Boren, 57, on his farm.