July 8 (UPI) -- Texas carried out the execution of Billy Joe Wardlow on Wednesday after the U.S. Supreme Court declined to issue a stay of execution.
Prison officials declared Wardlow, 45, dead at 6:52 p.m. at the Texas State Penitentiary at Huntsville, according to The Marshall Project, a criminal justice non-profit organization.
He was given the death penalty for the 1993 murder of 82-year-old Carl Cole.
The execution by lethal injection came shortly after the Supreme Court declined to issue a stay of execution in response to three petitions in recent weeks.
In one of the petitions, Wardlow asked justices to review his case in light of a 2005 ruling in which the high court outlawed the death penalty for those who committed murder when they were 17 years old or younger. The decision cited research that said that juveniles lacked the maturity and responsibility of an adult, and thus shouldn't be subject to the death penalty.
Wardlow, who was 18 at the time of Cole's death, argued that scientific research suggests that killers under the age of 21 should be given the same consideration.
"Neuroscientific research has established with scientific certainty that because of continuing brain development until sometime in our early 20s, the neurological basis for a person's character, and hence his or her character, is not fully formed prior to the age of 21," stated a filing Monday seeking a stay.
"Because of this, it is now clear that there can be no reliable prediction concerning future dangerousness for a person who has committed capital murder prior to the age of 21."
Wardlow's lawyers argued that because they believe he's likely to succeed in his appeal, the Supreme Court should stay his pending execution.
Robert Dunham, executive director for the Death Penalty Information Center, said Wardlow's case "epitomizes some of the worst aspects of the death penalty in the United States."
"While there is no question that Mr. Wardlow committed the murder, his death sentence was obtained through the use of junk-science predictions of future dangerousness -- the type of false and misleading evidence that should play no role in decisions whether a person should live or die," he said.
"A process in which the prosecutor is the ventriloquist, the state court is the dummy, and the federal courts are the audience pretending not to see the ventriloquist's lips move can hardly be considered fair, decent, or reliable. Yet that is what currently passes for judicial review in the Texas state and federal courts in death-penalty cases."
The Texas parole board voted 6-1 Monday not to lower Wardlow's sentence or recommend a commutation, according to The Texas Tribune.
Wardlow's death was the seventh execution in the United States and the third in Texas this year.