A Mississippi man scheduled to be put to death on Tuesday was granted a stay of execution by the State Supreme Court, after the United States Department of Justice sent lawyers and officials involved in the case several letters disavowing the degree of certainty expressed by F.B.I. forensic experts at the man’s trial.

About 2 p.m., just four hours before the scheduled execution, the court voted 8 to 1 to grant a reprieve “until further order” to Willie Jerome Manning, 44, who was convicted in 1994 of murdering two college students.

The justices in favor did not explain their reasoning or put a time limit on the reprieve. The dissenting justice issued a blistering objection, saying Mr. Manning had exhausted the challenges to his conviction and attacking the Justice Department for the letters, along with several other unrelated issues.

Starting Thursday, the Justice Department sent three letters calling certain aspects of the trial testimony of two F.B.I. experts “erroneous.” Defense lawyers cited these letters as reasons to put off the execution until DNA tests could be conducted on crime scene evidence, including a rape kit, a request that Mr. Manning had made unsuccessfully several times before.