FIRED FBI Director James Comey is well-known among his former colleagues as a prolific memo-writer, opening the possibility that more documents related to discussions between Comey and President Trump could be leaked in the coming days.

Fox News reports that in February, Comey wrote in a memo that Trump had asked him to shut down the investigation into former National Security Adviser Michael Flynn. The memo’s existence was first reported Tuesday by The New York Times and was confirmed by Fox News Wednesday.

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One Comey confidant told Fox News that the former FBI chief had made a “habit of memorialising important discussions he had with senior officials” over his decades-long law enforcement career. The source did not confirm the existence of more memos, but said it “stands to reason” that Comey made other notes about meetings with Trump.

Comey’s memo was made public weeks after the FBI interviewed Flynn regarding his contacts with the Russia ambassador to the United States and after the acting attorney general, Sally Yates, warned the White House that Flynn had misled them about those conversations and could be vulnerable to blackmail.

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Flynn was forced to resign Feb. 13, the day before the conversation between Trump and Comey depicted in the memo.

Comey was abruptly fired May 9 and learned of the dismissal as he was giving a talk in Los Angeles. While the White House initially cited a Justice Department recommendation and Comey’s very public handling of the Clinton email investigation as reasons, those explanations quickly shifted.

Following the memo’s release, some congressional Republicans criticised Comey for not reporting the conversation with Trump to his superiors at the Justice Department. However, a former U.S. government official told Fox News, “That’s not how it works.”

Comey was conducting an investigation as to whether President Trump was colluding with the Russian government,” the official said. “He’s not going to stop that in order to blow the whistle on a smaller crime (obstruction of justice).”

The official also said that “the FBI, or DOJ, would never indict a sitting president.

“You gather the information and you pass it on to Congress for what could end up in impeachment proceedings,” the official said, “and that passing of info to Congress is what you’re starting to see now.”

There is no sign the FBI’s Russia investigation is closing. Acting FBI Director Andrew McCabe told Congress last week the investigation is “highly significant” and said Comey’s dismissal would do nothing to impede the probe.