Some of the details of the letter President Trump drafted in May meant to explain why he fired FBI Director James Comey have now been revealed, according to a report Friday evening.

The letter, the existence of which was revealed earlier in the day and is now in the hands of special council Robert Mueller's team, made it clear that he wanted Comey gone because of the for top law enforcement official's refusal to publicly clear his name in the Russia investigation.

"You've told me three times I'm not under investigation but you won't tell the world, and it's hampering the country," an administration official said in paraphrasing what Trump wrote in the letter, the Wall Street Journal reported. Comey later testified before the Senate Intelligence Committee that during his time at the FBI, Trump was not under investigation in connection to the Russia probe.

Trump worked on the letter from his golf resort in Bedminster, N.J., with help from White House senior policy adviser Stephen Miller.

"It was the president's idea. Miller was the scrivener," the official added.

The duo cited a number of reasons Trump believed he was justified in firing Comey a week after the draft was written, but focused on Comey's telling Trump privately that he was not under investigation.

Trump never sent the four-page letter to Comey at the discretion of White House aides and Justice Department officials who urged him on May 8 to go in a different direction.

Instead, Trump issued a four-paragraph letter to Comey. Attorney General Jeff Sessions and Deputy Attorney General Rod Rosenstein also drafted memos outlining why they saw Comey unfit to continue serving as FBI chief.

The reason for Comey's dismissal was explained as his mishandling of Hillary Clinton's email investigation, which would seem to contradict the Russia focus Trump cited in his original draft.

Robert Mueller's special counsel team received the draft letter last month as is looking it over for a complete picture as to why Trump terminated Comey.