(CN) - A serial killer who attempted to block his execution by raising concerns about one of the lethal injection drugs to be used was put to death Thursday night in Virginia.
Alfredo Prieto was pronounced dead at 9:17 p.m. at the Greensville Correctional Center in Jarrat, Va.
Prieto, a native of El Salvador, was sentenced to death in 2010 for the rape and murder of 22-year-old Rachael Raver, and the murder of her boyfriend, Warren Fulton, in December 1988.
In September 2005, DNA evidence found at the crime scene and at that of another murder was matched to Prieto, who was then on death row in California for the murder of a 15-year-old girl in 1990. He was also a suspect in at least six other murders.
But as the day of Prieto's reckoning approached, Virginia's supply of the sedative it usually uses in the three-drug cocktail - midazolam -- ran out, and he challenged the safety of the revised drug protocol to be used to kill him.
On Wednesday, U.S. District Judge Anthony Trenga temporarily stay the execution to allow Virginia to provide details about the drugs. One of the drugs, pentobarbital, was obtained from the Texas Department of Corrections, but officials there offered only spotty details about where the drug came from.
Prieto's attorneys, Elizabeth Peiffer and Robert Lee argued the lack of information about the drugs put the state at risk of carrying out a cruel and potentially painful execution.
But after a hearing on Thursday, another judge, U.S. District Judge Henry Hudson, lifted the state, saying the attorneys failed to adequately demonstrate the drugs were unsafe.
In the meantime, the U.S. Supreme Court rejected Prieto's requests for a writ of certiorari and a writ of Habeas Corpus that he hoped would keep him alive.
Then early Thursday evening, the Fourth Circuit rejected a last minute appeal on the killer's behalf.
Prison officials said his last words were, "Get this over with."
Read the Top 8
Sign up for the Top 8, a roundup of the day's top stories delivered directly to your inbox Monday through Friday.