By Ian Simpson
WASHINGTON (Reuters) - A federal judge in Virginia on Wednesday ordered a temporary halt to a serial killer's execution scheduled for Thursday so a hearing could be held about one of the drugs that would be used to put him to death.
U.S. District Court Judge Anthony Trenga granted a temporary restraining order against Virginia and scheduled a hearing for 2 p.m. EDT on Thursday. Alfredo Prieto, 49, is set to be executed by lethal injection at 9 p.m. EDT on Thursday.
Prieto's lawyers asked Trenga to halt the execution until correctional officials say who the producer is of the pentobarbital to be used as part of a three-drug protocol.
They also want guarantees of the sterility and potency of the pentobarbital and documents showing how it was stored and shipped. The drug was produced by a compounding pharmacy and obtained from the Texas Department of Criminal Justice, according to a court filing.
Prieto, a native of El Salvador, was convicted in 2010 for the 1988 murders of Rachel Faver and her boyfriend Warren Fulton in Fairfax County, a Washington suburb. Faver had been raped.
Prieto was facing a 1992 death sentence in California for raping and murdering a 15-year-old girl when he was convicted in Virginia. California officials extradited him to Virginia.
Prieto has also been linked by DNA to a 1988 rape and capital murder in Virginia's Arlington County. Those charges were not prosecuted after Prieto was sentenced to death.
Prieto's lawyers have asked for a stay of execution from the U.S. Supreme Court to allow time for state and federal courts in California to rule on his claim that he is intellectually disabled.
They argue that Prieto has an IQ of 66 and is constitutionally exempt from execution. An IQ of 85 to 114 is considered average.
Virginia Governor Terry McAuliffe, a Democrat, this week denied a request for a reprieve.
The execution would be the first in Virginia since January 2013. The state has carried out 110 executions since the U.S. Supreme Court reinstated the death penalty in 1976, according to the non-profit Death Penalty Information Center.
(Reporting by Ian Simpson; Editing by Richard Chang and Mohammad Zargham)