Orlando Hall had been set to die by lethal injection at the US Penitentiary in Terre Haute, Indiana, for the murder of Lisa Rene.
Hall would have become the US government’s eighth execution this year if it had gone ahead as scheduled.
But the execution was put on hold by a federal judge just hours before it was due to be carried out, according to Reuters.
The judge postponed it after an appeals court this week found the government’s death penalty protocol violates federal law.
US District Judge Tanya Chutkan said the execution must be put on hold as the court weighs constitutional questions raised by Hall’s attorneys.
“The court is deeply concerned that the government intends to proceed with a method of execution that this court and the Court of Appeals have found violates federal law,” wrote Judge Chutkan.
Hall, 49, has spent 25 years on death row following his conviction for the murder of Ms Rene, who was killed after her brothers stole $4,700 during a drug deal.
Prosecutors said that Hall and four other men, who were involved in marijuana trafficking, drove from Arkansas to Arlington, Texas, to confront the brothers.
When they found their 16-year-old sister at home they took her at gunpoint back to Arkansas where she was raped, beaten unconscious and buried alive in a park.
Hall, who never denied involvement in the killing, is Black and was convicted by an all-white jury.
But his lawyers say that the jury would not have sentenced him to death if they knew “key facts” about the case.
Three of the other men signed plea deals that gave them prison time for testifying against Hall and Bruce Webster, and have already been released.
If the execution goes ahead Hall would be the eighth person killed by the federal government since the Justice Department resumed executions in July after a 17 year pause.
Before that only three people had been executed by the federal government in the previous 50 years.
Earlier a federal judge also blocked the government’s plan to execute the first female death row inmate for six decades after her lawyers caught the coronavirus visiting her in prison.
Lisa Montgomery had been due to die at the same prison complex on 8 December but her lawyers want to file a clemency petition on her behalf.