The Mississippi Supreme Court has blocked the execution of Willie Jerome Manning, which had been scheduled for Tuesday evening.
Manning had been set to die by injection shortly after 6 p.m. at the state prison in Parchman for the 1992 slayings of two college students.
The court said the execution should be delayed until it rules further on the case.
The FBI has said in recent days that there were errors in agent's testimony about ballistics tests and hair analysis in the case. Manning was convicted in 1994.