Former Attorney General Eric Holder says FBI Director James Comey screwed up when he told Congress he found more emails that could be related to its investigation into Hillary Clinton's private email server.

"That decision was incorrect," Holder wrote in the Washington Post late Sunday. "It violated long-standing Justice Department policies and tradition."

Comey told Congress on Friday that while he said his investigation into Clinton was thought to be complete, more possibly pertinent emails were found on a computer used by Clinton's top aide, Huma Abedin, and her estranged husband, former Rep. Anthony Weiner, D-N.Y.

Democrats blasted Comey's announcement of the move, and said it politicized the investigation with just two weeks left before the election. Some Democrats said Comey may have broken the law by taking that step.

Holder said at a minimum, Comey violated Justice Department policy and his own guidance.

"[I]t ran counter to guidance that I put in place four years ago laying out the proper way to conduct investigations during an election season," Holder wrote. "That guidance, which reinforced established policy, is still in effect and applies to the entire Justice Department — including the FBI."

Holder also said his former department has a policy of not commenting on ongoing investigations, or even acknowledging they exist," he said.

"Director Comey broke with these fundamental principles," Holder wrote. "I fear he has unintentionally and negatively affected public trust in both the Justice Department and the FBI."

Holder said he also disagreed with Comey's July press conference in which he said he was not recommending any charges against or her team.

"Instead of making a private recommendation to the attorney general — consistent with Justice Department policy — he chose to publicly share his professional recommendation, as well as his personal opinions, about the case," he wrote. "That was a stunning breach of protocol. It may set a dangerous precedent for future investigations. It was wrong."