Texas has put to death a serial killer, after the US Supreme Court rejected his last-ditch appeal over the source of lethal injection drugs.
The execution on Thursday of Tommy Sells, who was convicted of murdering a 13-year-old girl in 1999 but who has claimed responsibility for dozens of killings, came after a lower court ordered authorities in Texas to provide more information about the origin of drugs to be used in their lethal injections.
A judge had tossed the lower court ruling on appeal on Wednesday, and Sells's execution was back on schedule.
Lawyers for Sells had demanded to know the name of the pharmacy supplying Texas with pentobarbital, in order to check the quality of the execution drug and spare their client from unconstitutional pain and suffering.
Sells, 49, was pronounced dead at 6.27pm (1027 AEDT).
He was the 15th death row inmate to be put to death in the United States this year, and the fifth in Texas alone.
Last year, the Lone Star State accounted for more than a third of all US executions, according to the Death Penalty Information Center.
US states using the death penalty have faced crisis over shortages of lethal injection drugs after European suppliers stopped supplying pentobarbital for use in human executions.
The shortage has prompted many US states to turn to unregulated compounding pharmacies to supply the drugs instead.
However, lawyers for many prisoners have said the compounded drugs can cause excruciating pain, putting executions using them in violation of the US Constitution, which forbids cruel and unusual punishment.
Texas authorities said the substances to be used in the executions had been tested and were found to be free of contaminants.
