Six former top Justice Department leaders are urging the U.S. Supreme Court to vacate a murder conviction that they say poses an existential threat to the entire justice system, after a Mississippi prosecutor repeatedly blocked black citizens from serving on the defendant's six juries.

Former Acting Attorney General Sally Yates, former Acting Attorney General Peter Keisler and four other former DOJ luminaries — represented by former Solicitor General Donald Verrilli — filed an amicus brief Thursday in Curtis Flowers' case, which the U.S. Supreme Court agreed to hear in November.

Flowers was put on trial six times over a killing of four people at a Mississippi furniture store and prosecuted every time by Doug Evans, whose jury selection practices the Mississippi Supreme Court found racially discriminatory in at least one of the trials.

But the final guilty verdict secured by Evans — using the same practices, according to Flowers' lawyers at Cornell Law School — was finally good enough for the Mississippi Supreme Court, which upheld the conviction in 2014 and then, after a brief detour in which the U.S. Supreme Court asked it to take note of a new 2016 precedent, affirmed it again in 2017. The former DOJ officials said Thursday that that affirmation shouldn't stand.

"Preventing racial discrimination in jury selection is essential to preserving both the principle of equal justice under law and public confidence that it is being upheld," the officials said.

"In particular, this court's precedent mandates, contrary to the decision below, that evidence of a prosecutor's prior history of racial discrimination is critical context that — in connection with evidence of discrimination intrinsic to the voir dire proceeding — is sufficient to provide an 'undeniable explanation' that the prosecutor's proffered reasons for striking African American jurors are pretext," they said.

But the Mississippi Supreme Court ignored Evans' history of discrimination, they said.

Yates and Keisler are joined by former deputy attorneys general Donald Ayer, James Cole and David Ogden, and former Acting Deputy Attorney General Gary Grindler.

Flowers was first tried in 1997 in connection with the gruesome 1996 killings at the Tardy Furniture Store in Winona, Mississippi. In 2000, 2003, and 2007, the Mississippi Supreme Court overturned the first three convictions and death sentences obtained by Evans. In two subsequent trials, juries were hung. The sixth and most recent trial yielded a fourth conviction and fourth death sentence.

The American Public Media podcast "In the Dark" undertook an exhaustive investigation of Flowers' story and concluded it was deeply unlikely, if not impossible, that Flowers actually committed the murders.

That is not the issue in this appeal, however. Instead, the nation's high court will review prosecutor Evans' use of peremptory strikes to assemble all-white or nearly all-white juries in most of the six trials.

"When there is reason to believe that a prosecutor is exploiting racial bias and division in an attempt to obtain a conviction, the courts must take strong action. That the bias is exploited by, or seen to be exploited by, prosecutors — public servants who have been charged with promoting fairness and justice — makes this type of discrimination especially damaging to acceptance of the rule of law," the former DOJ officials said Thursday.

Evans' pattern of striking black jurors was one the Mississippi Supreme Court was well aware of, having overturned conviction number three on just such "Batson" grounds. Batson is the 1986 U.S. Supreme Court decision prohibiting racial discrimination in the use of jury peremptory strikes.

Evans committed identical Batson violations in the sixth trial, according to Flowers' high court brief, filed Dec. 27.

In that trial, Evans accepted the first black juror who came up, and then struck five others, resulting in a panel of 11 white jurors and one black one. He "materially misrepresented the facts" that provided supposedly race-neutral grounds to get rid of four of the struck five African-Americans — for example, lying that some of these jurors knew witnesses, according to Flowers' brief. Flowers was convicted and sentenced to death.

In refusing to disturb the conviction, Mississippi's high court said in 2017 that great deference was owed the trial court, and that the trial court had taken into full consideration Evans' history when Flowers' counsel made Batson arguments at trial.

"The trial court was presented with and rejected Flowers's present [Batson] argument that he had advanced at trial," the state high court said in 2017. "Flowers's counsel ensured that the trial court consider the totality of the circumstances, including historical evidence of racial discrimination by the district attorney. ... The prior adjudications of the violation of Batson do not undermine Evans's race neutral reasons."

Oral arguments at the high court will likely center on the permissibility of excising key context from a Batson analysis.

"In its post-Batson jurisprudence, this court has held that the prosecution's prior pattern of racial discrimination is powerful evidence that peremptory strikes of African American jurors in a particular case may be discriminatory," the DOJ officials said Thursday.

Mississippi will file its own Supreme Court brief in the coming months, but in the state's July filing opposing Flowers' bid for review, it said the state high court "properly applied the well-settled principles of this court's Batson jurisprudence in deferring to the trial court's factual findings."

Flowers "asks the [U.S. Supreme] Court to assume the prosecutor violated Batson in this case because the prosecutor was found by four justices of the Mississippi Supreme Court to have violated Batson in Flowers III. This is inconsistent with this court's Batson jurisprudence," it said.

Verrilli and the Mississippi Attorney General's Office did not immediately respond to requests for comment. Counsel for Flowers declined to comment.

--Editing by Brian Baresch.

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