Detectives searching a car in which two bullet-riddled bodies were abandoned in a Lubbock gully also found an inch-long fingertip of a latex glove on the bloody floor of the back seat.
DNA tests tied the glove to Texas Tech doctoral student Vaughn Ross.
Blood on the glove fragment also came from one of the murder victims, 53-year-old Douglas Birdsall, an associate dean at Tech.
The other shooting victim was an 18-year-old woman.
Attorneys for Ross now hope the U.S. Supreme Court will block the 41-year-old inmate's execution set for Thursday evening in Huntsville.
His lethal injection would be the second this week in Texas. Convicted killer John Quintanilla was executed Tuesday evening for a 2002 slaying during a holdup in Victoria.