Update 3:04 p.m.: The Mississippi Supreme Court has granted a stay of execution, although it's unclear on what grounds the court made the determination. This means Manning's execution, which had been scheduled for 6 p.m. CDT, will not go forward.

A Mississippi death row inmate is just hours from execution as his attorneys urge the state to conduct DNA testing the lawyers say may prove Willie Jerome Manning is innocent.

But as of Tuesday morning, it remained unclear whether Mississippi Gov. Phil Bryant would order a stay of execution for Manning, a black man convicted of murdering two white Mississippi college students. A spokesman for the governor could not immediately be reached for comment.

A stay or reprieve would be Manning’s only options to avoid execution, which is slated to go ahead at 6 p.m. Tuesday local time. The Mississippi Supreme Court denied a motion by Manning’s lawyers to delay the execution so DNA testing can be conducted -- evidence that Manning says will exonerate him of the crimes.

“If the governor doesn’t step in and order a stay or reprieve, the execution will go forward,” Will McIntosh, staff attorney for the Mississippi Innocence Project, a nonprofit that is playing an ancillary role in Manning’s defense, told the International Business Times.

Manning was convicted in 1994 by a majority-white jury of the murders despite no physical evidence linking him to the killings of white Mississippi State University students Jon Steckler and Tiffany Miller back in 1992. Earl Jordan, an inmate who initially claimed Manning confessed to the murders, later recanted his testimony. Paula Hathorn, a woman facing criminal charges in Mississippi, used leading questions to get Manning to confess the crimes and recorded the exchange for prosecutors, according to Manning’s attorneys.

On Monday, the U.S. Justice Department sent an email to Oktibbeha County District Attorney Deforest R. Allgood -- the jurisdiction where Manning was tried and convicted – saying that a review of the case by the department and the FBI found that “testimony containing erroneous statements” was given.

An FBI hair analyst who said hair fibers found at the crime scene were linked to Manning could not be supported by science “and was, therefore, invalid,” wrote John Crabb Jr., special counsel for Justice.

Crabb said other issues were found with an FBI firearms examiner who testified in the case.

“The science regarding firearms examinations does not permit examiner testimony that a specific gun fired a specific bullet to the exclusion of all other guns in the world,” he wrote, adding that the examiner “could testify to that information, to a reasonable degree of certainty, but not absolutely.

“As with any process involving human judgment, claims of infallibility or impossibility of error are not supported by scientific standards.”

While the FBI offered to conduct DNA testing using modern technology that wasn’t available at Manning’s trial, the Mississippi Supreme Court ruled against the motion filed by Manning’s lawyers requesting such testing.

The court claimed that Manning is just using the DNA angle to stall his execution and also argued that if DNA testing is allowed, it would prolong the case for years.

“I don’t see how it would be to the detriment to the people of Mississippi to have the (DNA) material tested,” McIntosh said.

Mississippi Attorney General Jim Hood agreed with the court’s decision, and said that Manning’s lawyers haven’t produced any new evidence that would exonerate Manning.

McIntosh said he hoped Bryant would give a stay or a reprieve.