A federal judge ordered the Department of Justice (DOJ) to give former FBI Director James Comey all materials it presented to a grand jury to secure a two-count indictment against him in September.

The order marks a significant blow to the DOJ’s case against Comey, which is part of President Donald Trump’s wider effort to wield the department against his longtime perceived enemies.

In his ruling Monday, Magistrate Judge William Fitzpatrick said his review of the materials revealed “substantive irregularities” that may arise to “misconduct” on the part of the DOJ. These concerns, the judge said, warrant disclosure of grand jury materials to Comey — a move that almost never happens in criminal proceedings.

“The Court recognizes that the relief sought by the defense is rarely granted,” Fitzpatrick wrote. “However, the record points to a disturbing pattern of profound investigative missteps, missteps that led an FBI agent and a prosecutor to potentially undermine the integrity of the grand jury proceeding.”

“Here, the procedural and substantive irregularities that occurred before the grand jury, and the manner in which evidence presented to the grand jury was collected and used, may rise to the level of government misconduct resulting in prejudice to Mr. Comey,” the judge added.