A Texas appeals court on Tuesday halted the execution of a man who has spent more than 30 years on death row and had been set to die by lethal injection this week over the killings of six girls and young women found buried in the desert near El Paso.

State prosecutors withheld evidence favorable to Brittany Marlow Holberg during her 1998 murder trial that resulted in her being sentenced to death, a federal appellate court panel ruled Friday.

A federal appeals court has tossed an Amarillo woman’s death sentence after it found that local prosecutors had failed to reveal that their primary trial witness was a paid informant.

Executions by firing squad are permitted in five states, but the new law will make Idaho the only state in which death by firing squad is the primary form of execution.

Idaho Gov. Brad Little signed a bill on Wednesday making death by firing squad the preferred method for executions, and death by lethal injection the second preferred method.