A federal judge has stayed Thursday night's scheduled execution of a serial killer until Texas reveals where the latest batch of lethal drugs came from.

Tommy Sells claims to have killed 70 people, including the 1999 stabbing death of a 13-year-old Del Rio girl, where he also slashed the throat of a 10-year-old who survived.

He's one of two death row inmates who asked the state of Texas to give them the name of their lethal drug supplier, or halt their executions.

“Many of these production facilities and compound pharmacies have had extremely spotty records and that can be the basis that the drugs are not appropriate for their intended use,” says Sells' attorney Jonathon Ross.

Ross tells KTRH News the supplier's name is important for determining whether their drugs are humane for executions.

The state argues some pharmacies have been threatened for supplying execution drugs.  Ross calls that a 'red herring.'

“We're not seeking to publicize the facility's name, so it would not have any public ramifications, and those issues are irrelevant to our request,” he says.