The executions of three Indiana inmates scheduled for the same week in May have been put on hold as the U.S. Supreme Court considers a case that has sparked debate over the mix of drugs used to carry out death sentences.

The three inmates held at the Terre Haute federal prison were convicted in 1993 of killing nine people in drug-related crimes in Virginia. All three — Richard Tipton, Cory Johnson and James H. Roane Jr. — were to be executed the week of May 8.

Their attorneys sought to have the executions blocked until after the Supreme Court rules on whether a Florida inmate was wrongly barred from pursuing a claim that the lethal drugs cause pain in violation of the constitutional protection against cruel and unusual punishment.

The U.S. Justice Department did not oppose the defense motion, saying the Supreme Court's ruling might prevent the three inmates from challenging the federal method of execution. All three were condemned for their role in a drug ring. The nine people they were convicted of killing in early 1992 were suspected informants, competitors and underlings. Authorities said one man was stabbed 84 times for mishandling a drug transaction.

The inmates in December challenged the federal execution method, claiming that while sodium pentothal “supposedly will render the plaintiffs insensible to the pain of their deaths, it in fact can and will merely cast a ‘chemical veil' over this excruciating pain, leaving plaintiffs conscious but trapped in a paralyzed body wracked with the pain of suffocation and heart attack.”

The Supreme Court is scheduled to hear arguments in the Florida case April 26, with a ruling before July.