Washington - Texas on Wednesday executed a man convicted of killing both his ex-girlfriend and her brother, officials said amid controversy over the drugs used to put him to death.
African-American Willie Trottie, aged 45, was declared dead at 18:35 in the execution chamber in Huntsville, Texas, said Jason Clark, a state correctional spokesman.
Trottie was tried and convicted for killing his ex-girlfriend, then 24, and her brother, aged 28, in Houston in 1993.
He was executed with a lethal dose of pentobarbital, a barbiturate.
However, US states using the death penalty are facing critical shortages of the injection drug after European firms stopped supplying it.
The shortage has prompted many states to turn to unregulated compounding pharmacies to supply the drug instead.
Trottie had filed an appeal demanding the name of the manufacturer of the execution medication, to determine if he was likely to suffer extensively.
Death penalty opponents allege that three recent US executions, which left inmates suffering for more than an hour at times instead of 10 minutes amount to a form of torture or the "cruel and unusual" punishment forbidden by the US constitution.
"This is the fifth such challenge to Texas' execution protocol in the last year. Each time, the plaintiffs represented by the same attorney have made exactly the same allegations", the state said in its response to the supreme court.
"Like the four plaintiffs before him, he continues to demand more information about where, how, who. Specifically, he wants to know the source of the pentobarbital", the state of Texas said, refusing to give the information.
Eighteen US states have abolished the death penalty, but 32 others, and the federal government maintain the practice, and polls suggest it retains majority support among the US public.
The governor is a member of the conservative National Action Party, or PAN, and the federal government is controlled by the Institutional Revolutionary Party.
State governors in Mexico have a long history of using local resources as they please. Even some members of PAN, like former Senator Javier Castelo Parada, questioned whether Padres was truly angry about the mine spill or was trying to divert attention from his family's dam and another controversial dam project he backed that draws water claimed by the state's Yaqui Indians.
"All of this is a political maneuver by the governor of Sonora to divert attention" from the other problems, Castelo Parada said.
He said environmental protection and the law often get lost in such political battles, which focus more on political rivalries than protecting waterways in an increasingly dry nation.
"It's a shameful situation", Castelo Parada said. "The rule of law is subordinated to political considerations."