HUNTSVILLE, Texas (AP) -- Attorneys for a serial killer asked the U.S. Supreme Court to halt his execution set for Thursday in Texas as they challenge that state's refusal to release information about where it gets its lethal injection drug.
Lawyers for Tommy Lynn Sells made the plea after a federal appeals court allowed the execution to remain on schedule. A lower court had stayed the execution Wednesday, ordering Texas to reveal more information about its drug supplier, but the ruling was quickly tossed on appeal.
"It is not in the public interest for the state to be allowed to be deceptive in its efforts to procure lethal injection drugs," Sells' attorneys told the high court.
The appeal was one of two pending before the justices. Another before the court since last month asked for the punishment to be stopped to review whether Sells' legal help at his trial was deficient, and whether a court improperly denied him money to hire investigators to conduct a probe about his background.
Sells was sentenced to death for fatally stabbing a 13-year-old South Texas girl in 1999. Court records show he claims to have committed as many as 70 killings in states including Alabama, California, Arizona, Kentucky and Arkansas.
The 49-year-old is scheduled to be lethally injected Thursday evening in Huntsville.
Sells' attorneys argue that they need to know the name of the company now providing the state with pentobarbital, the drug used during executions, in order to verify the drug's quality and protect Sells from unconstitutional pain and suffering.
But the 5th U.S. Circuit Court of Appeals sided with Texas prison officials, who argued that information about the drug supplier must be kept secret to protect the pharmacy from threats of violence. It also found that the stock of the pentobarbital, a powerful sedative, falls within the acceptable ranges of potency.
The court said that had Texas wanted to use a drug never used before for executions or a completely new drug whose efficiency or science was unknown, "the case might be different."
The Supreme Court last month rejected similar arguments from a Missouri inmate's attorneys who challenged the secrecy surrounding where that state obtained its execution drugs, and the condemned prisoner was put to death.
Questions about the source of execution drugs have arisen in several states in recent months as numerous drugmakers -- particularly in Europe, where opposition to capital punishment is strongest -- have refused to sell their products if they will be used in executions.
That's led several state prison systems to compounding pharmacies, which are not as heavily regulated by the U.S. Food and Drug Administration as more conventional pharmacies.
A batch of pentobarbital that Texas purchased from a compounding pharmacy in suburban Houston expired at the end of March. The pharmacy refused to sell the state any more drugs, citing threats it received after its name was made public.
That led Texas to its new, undisclosed suppler.
The court case challenging the state's stance also included 44-year-old Ramiro Hernandez-Llanas, who is scheduled for execution next week. But the 5th Circuit ruling affected only Sells.
Maurie Levin, an attorney for the inmates, said the lower court ruling, which had ordered the Texas Department of Criminal Justice to give defense attorneys details about the drug supplier and how the drug was tested, "honors the importance of transparency in the execution process."
Sells' execution would be the fifth lethal injection this year in Texas, the nation's busiest state for the death penalty.
A jury convicted him of capital murder in 2000 for the stabbing of 13-year-old Kaylene Harris and slashing of her 10-year-old friend, Krystal Surles, who survived and helped police find Sells. The girls were attacked on New Year's Eve 1999 as they slept in Harris' home in Del Rio, about 150 miles west of San Antonio.