A Texas killer scheduled for the nation's first execution since a botched lethal injection in Oklahoma filed a new round of appeals on Monday.
Robert James Campbell, 41, asked the Fifth U.S. Circuit Court of Appeals to halt Tuesday's execution on the grounds that the state has refused to say where it obtained the deadly drugs.
The appeals panel has declined in the past to issue stays of execution because of drug-secrecy policies, but the new challenge is being pressed just a few weeks after the Oklahoma debacle focused new attention on how states kill death-row inmates.
In Oklahoma, where a new drug combination was used for the first time, Clayton Lockett appeared to regain consciousness and writhe and moan in pain mid-execution, witnesses said.
Prison officials later said his vein collapsed, but no autopsy report has yet been issued. The state has halted executions while an investigation is under way.
Texas, which uses a different drug, has said the problems in Oklahoma should not affect its executions, but at least one federal judge disagrees.
In a ruling late last week, District Judge Keith Ellison suggested Lockett's death "requires sober reflection on the manner in which this nation administers the ultimate punishment."
Nevertheless, Ellison said he could not stop Campbell's execution because of earlier rulings by the Fifth Circuit.
Campbell is also asking the Texas Board of Pardons and Paroles to consider a recommendation for clemency on the grounds that the state allegedly withheld information that his IQ is low enough that he should be considered mentally retarded and ineligible for capital punishment.
A state court has already rejected an appeal on those grounds.
Campbell is on death row for the 1991 rape and murder of bank teller Alejandra Rendon. Her cousin told NBC News that no matter what happens Tuesday, the inmate's death won't be as cruel as his victim's.
"Nobody can even fathom the terror she went through," he said.