Investigators hold letter explaining Comey firing

The letter written by US President Donald Trump in the days leading up to former FBI Director James Comey's dismissal was reportedly withheld at the behest of the president's lawyers.

According to The New York Times, that letter is now in the possession of special counsel Robert Mueller and his team, as they probe whether Trump fired Comey to impede an FBI investigation into ties between the president's campaign aides and Russian officials.

Read more: What you need to know about special counsel Robert Mueller's investigation into the Trump campaign

On May 9, the day of Comey's ousting, the White House released a letter signed by Deputy Attorney General Attorney Rod Rosenstein citing the FBI director's handling of the Hillary Clinton email case as justification the dismissal. Trump then said he had acted on the Justice Department's recommendation.

Just days later the commander-in-chief admitted in the television interview that the "Russia thing" had had a bearing on his decision and that he would have fired Comey "regardless of recommendation."

According to reports citing White House sources, Trump had been fuming for weeks over Comey's refusal to publically state that he was not directly implicated in the FBI's investigation, something the president claimed he had been assured of several times in private. The newly uncovered letter is believed to reflect those sentiments from the president, as well as a host of further complaints against Comey.

The New York Times also revealed, citing two anonymous sources familiar with the situation, that in early May, Trump had asked White House aide Stephen Miller to draft letter outlining the rationale for ousting Comey. Miller has become a trusted adviser to the president since the campaign and has helped Trump draft his hardline immigration and travel ban policies.

Read more: Trump’s justification of firing Comey looks like obstruction of justice

The latest allegations came a day after the Senate Judiciary Committee released interview excerpts from their investigation into whether Comey had violated federal laws barring government officials from using their position to influence an election. The FBI director famously announced just days before the November election last year that the bureau was reopening its investigation into Democratic candidate Hillary Clinton's use of private email servers.

Trump flared up again following the release of the excerpts, posting on Twitter that Comey had exonerated Clinton months before the investigation had actually ended, ascribing it to a "rigged" political system.

The Senate Committee's probe into Comey was closed following his firing in May.

dm/sms (AP, dpa)