Citing a recent court ruling, three candidates for San Francisco district attorney insisted Tuesday that George Gascón, the interim DA who is running for a full term, release an internal memo detailing missteps and shoddy procedures at the San Francisco Police Department’s beleaguered crime lab.

Sharmin Bock, a candidate and an assistant district attorney in Alameda County, called the memo “the single greatest threat to criminal justice in San Francisco,” because it could sway the outcome of hundreds of violent crime cases.

“Don’t cover it up; fix it,” Bock said. “Cases are jeopardized because the DA is not following the law.”

Gascón's rivals, who have been pressuring him to release the memo for weeks, have new support for their demands: In an opinion that reverberated through local law enforcement circles, a San Francisco Superior Court judge last week ordered that the memo be made available to defense lawyers, because it contains evidence that could help exonerate criminal defendants.

The district attorney's office has consistently argued that it has no legal obligation to release the confidential memo.

The disclosure of the memo at the height of campaign season could embarrass police officials and Gascón, the former police chief who has been accused by his political opponents of suppressing the document for the past year.

Gascón’s office said Friday that it intends to appeal the court order to release the memo — a decision that his three challengers took turns lambasting on Tuesday before a small group of reporters.

Speaking on the steps of City Hall Tuesday, Bock was flanked by two of her rivals, David Onek, a fellow at the Berkeley Center for Criminal Justice, and Bill Fazio, a criminal defense attorney. The three candidates, who in recent weeks have made a calculated decision to join forces against Gascón, the front runner, unfurled a large, full-color banner that read: “What is George Gascon hiding in his secret DNA Crime Lab file?”

"This is an extremely troubling situation, that a judge has ordered the release of a document that has been consistently covered up and suppressed," Onek said.

Maggie Muir, Gascón’s campaign manager, dismissed the event as “another desperate attempt to gain media attention for their campaigns that are getting no traction.”

“There’s nothing newsworthy here,” she added.