The Oklahoma Department of Corrections is preparing to carry out its first execution Wednesday since a sharply divided U.S. Supreme Court upheld the state's three-drug formula used in lethal injections.
Richard Glossip, 52, is scheduled to be executed at 3 p.m. at the Oklahoma State Penitentiary in McAlester.
He was convicted of ordering the beating death of a motel owner in 1997 in what prosecutors say was a murder-for-hire.
Glossip was the lead plaintiff in a case before the nation's high court that argued the sedative midazolam violated the U.S. Constitution's ban on cruel and unusual punishment because it didn't adequately render an inmate unconscious before the second and third drugs were administered.
The justices upheld the formula in a 5-4 opinion issued in late June.
Glossip has maintained his innocence, and his attorneys filed a last-minute request for a stay of execution late Tuesday.
On Tuesday, Governor Mary Fallin issued a statement rejecting a stay of execution requested by Glossip's attorneys Monday.
News On 6 anchor and Crime Reporter Lori Fullbright will be in McAlester this afternoon for the execution.
The Associated Press contributed to this report.