Attorneys for condemned inmate Cary Kerr are trying to keep him from becoming the first Texas prisoner executed with a new drug.
The 46-year-old man is set to die Tuesday in Huntsville for the rape-slaying of a woman near Fort Worth 10 years ago.
Texas is switching to pentobarbital as one of the three drugs in the lethal injection process because of a nationwide shortage of sodium thiopental, a sedative previously used.
But appeals Monday before the U.S. Supreme Court are focusing whether Kerr received adequate legal help during earlier appeals of his conviction and death sentence.
Kerr was convicted of the July 2001 slaying of 34-year-old Pamela Horton. Her body was dumped on a Tarrant County street. Kerr has denied killing the woman.