"I will be fine," James Comey says in email to FBI after being fired

Last Updated May 10, 2017 10:41 PM EDT

A day after being fired by President Trump, FBI Director James Comey wrote an email to the bureau explaining that he is "not going to spend time" thinking about the decision to fire him or how it was executed.

"I will be fine," Comey assured his former staffers.

CBS News obtained a copy of the email, which wasn't sent by Comey himself but was forwarded by someone within the bureau. The email's existence was first reported by CNN.

Comey wrote that he has "long believed the president can fire an FBI Director for any reason or for no reason at all" and said he will not question that decision -- and he hopes no one else will.

"I have said to you before that, in times of turbulence, the American people should see the FBI as a rock of competence, honesty and independence," the email read. "What makes leaving the FBI hard is the nature and quality of its people, who together make it that rock for America."

Comey wrote that "working with you has been one of the great joys of my life."

Several FBI employees and agents told CBS News they were touched by what they took as the very personal nature of the farewell email, especially after the abrupt announcement of his dismissal on Tuesday.

After Comey's dramatic firing, current and former FBI agents and employees told CBS News they were shocked by the decision.

"I am not happy. I think this is bulls--," one current special agent told CBS News. "We are living in partisan times. Both sides criticized the director; that's why he should still be in the job. The vast majority of the bureau is in favor of director Comey."

Agents and employees told CBS News that they take issue with White House spokeswoman Sarah Huckabee Sanders' comments that Comey had lost the confidence of the bureau.

The White House said Wednesday that Comey had been fired because Mr. Trump had lost confidence in him. But many have questioned the timing, since the FBI is leading the investigation into ties between the Trump White House and Russia. 

Sources tell CBS News that just last week, Comey asked Deputy Attorney General Rod Rosenstein for more resources for the FBI's Russia investigation, something the Justice Department denies. 

CBS News' Andres Triay contributed to this report.