WASHINGTON – The Supreme Court halted an execution in Mississippi Tuesday, less than an hour before a convicted killer was scheduled to be put to death by lethal injection.

The last-minute reprieve for Earl Wesley Berry is the third granted by the justices since they agreed late last month to decide a challenge to Kentucky’s lethal injection procedures.

Justices Samuel Alito and Antonin Scalia would have allowed the execution to go forward.

Berry was convicted of kidnapping a woman in 1987 and beating her to death before dumping her body in the woods. His execution was planned for 7 p.m. EDT.

The Supreme Court has allowed only one execution to go forward since agreeing to hear the Kentucky case. Michael Richard was executed in Texas on Sept. 25, the same day the court said it would hear a lethal injection challenge from two death row inmates in Kentucky. State and lower federal courts have halted all other scheduled executions since then.

Berry asked for a delay at least until the court issues its decision in the Kentucky case. He claims the mixture of deadly chemicals Mississippi uses will cause unnecessary pain, constituting cruel and unusual punishment.