The Justice Department has acknowledged flaws in forensic testimony by the FBI that helped convict a man in the 1992 slayings of two Mississippi State University students, and federal officials have now offered to retest the DNA in the case.

The extraordinary admission and offer come just days before the man is scheduled to die by lethal injection on Tuesday and present a quandary for Mississippi officials about whether to stop the execution of Willie Jerome Manning, 44.

Manning’s lawyers asked Gov. Phil Bryant (R) for a stay. Bryant spokesman Mick Bullock said in a written statement Friday that the governor is reviewing the facts of the case.

Federal officials found Manning’s case as part of a broad review of the FBI’s handling of scientific evidence in thousands of violent crimes in the 1980s and 1990s.

The Justice Department announced last summer an effort to correct past errors in forensic hair examinations before 2000 — at least 21,000 cases — to determine whether agents exaggerated the significance of purported hair “matches” in lab reports or trial testimony.

The reviews were prompted by a series of articles in The Washington Post that found that the Justice Department ignored warnings about widespread problems in cases that relied on hair identification.

Manning’s case presents a difficult first test of the Justice Department review. Last week, the Mississippi Supreme Court denied a request by Manning’s lawyers to reexamine a rape kit, fingernail scrapings, hairs and fingerprint evidence in the case, ruling narrowly that even if Manning’s DNA was absent, that would not be enough to overturn his 1994 conviction.

“Our examination anew of the record reveals that conclusive, overwhelming evidence of guilt was presented to the jury,” Presiding Justice Michael K. Randolph wrote for the 5 to 4 majority.

Oktibbeha County District Attorney Forrest R. Allgood said Manning was separately convicted and sentenced to death for killing two elderly women in their apartment in 1993 in Starkville, Miss. He questioned the defense tactics and said any reconsideration of the students’ case should include consultation with the victims’ families.

“The bottom line is when you start looking at these things, there’s always something else you can do and it never ends,” Allgood said.

Manning defense attorney David Voisin said that both sets of convictions are on appeal and that new testing could identify the students’ actual attacker. While investigators could not detect biological evidence of rape two decades ago, the female victim was found with her pants and underwear pulled down, and DNA testing is far more sensitive today and could potentially identify a culprit, he said.

“I commend the FBI for being diligent, reviewing their prior work, and recognizing the need for testing,” Voisin said. “We’re hoping that the governor will do the same thing.”

Legal experts also praised federal authorities for undertaking the fuller review and urged Mississippi officials to press forward with the testing. “There is really no good reason not to allow DNA testing, particularly in capital cases,” said Myrna Raeder, a Southwestern University Law School professor and co-chair of the innocence committee of the American Bar Association’s Criminal Justice Section. “We’re still not completely to the point where we’re willing to recognize that science may and should overrule some of our judicial rules that may make sense in terms of finality but make no sense in terms of determining innocence.”

Manning was convicted of kidnapping and killing students Jon Steckler and Tiffany Miller, whose bodies were discovered some distance from Mississippi State University’s campus on Dec. 11, 1992. Each was shot to death, and an FBI expert, Chester E. Blythe, testified that African American hair fragments were found in Miller’s car.

Manning is black. Steckler and Miller were white.

Randolph noted that prosecutors found that Manning was arrested after trying to sell Steckler’s leather jacket and class ring and a compact disc player from his car. Manning’s cousin and a jailhouse informer each said that Manning confessed to them.

Writing in dissent before federal authorities came forward, Mississippi Supreme Court Justice James W. Kitchens called for further testing, saying that otherwise, “the investigation of these horrible crimes will remain incomplete.”

Kitchens noted that Manning’s cousin gave several versions of his story, earlier implicating two other men and then stating that Manning confessed to the killings with a second man.

In addition, the jailhouse informer recanted his testimony, and Manning has maintained that he was selling property stolen by someone he didn’t know.

Fingerprints found in one victim’s car were not matched to Manning or the victims and have never been checked against government databases.

“The victims’ families and the public at large deserve to know whether another, or an additional, perpetrator was involved,” Kitchens wrote. “Interests far beyond Manning’s are at stake, and whatever potential harm the denial seeks to avert is surely outweighed by the benefits of ensuring justice.”

In a letter dated Thursday, John Crabb Jr., special counsel to the Justice Department, told lawyers in the case that Blythe “exceeded the limits of the science” when he testified that he could match a crime-scene hair to an individual with “a relatively high degree of certainty.”

“In the event that your office determines that further testing is appropriate or necessary, the FBI is available to provide mitochondrial DNA testing of the relevant hair evidence or [DNA] testing of related biological evidence” in some circumstances, Crabb wrote.

Allgood, the prosecutor, said that because Blythe said he could not “match” Manning to the crime-scene hairs because only fragments were recovered, the FBI’s acknowledgment of the error is irrelevant.

“Functionally it affects nothing, because he [Blythe] didn’t testify that this is the guy the hairs came from,” said Allgood, who has served as the county prosecutor since 1989 and tried Manning.

In a statement, the FBI said Manning’s case was reviewed this week after the FBI learned that Mississippi had set the May 7 execution date.

Late Friday, attorneys for the Mississippi Innocence Project and Manning’s brother asked the court to bar the state from destroying DNA evidence that could be retested even if the execution goes forward.