Story highlights The tweet represented a remarkable show of frustration by a serving President

Aides said that the President had decided to take matters into his own hands

(CNN) President Donald Trump complained in a furious Friday morning tweet that he was being investigated for firing former FBI Director James Comey and seemed to accuse the deputy attorney general of overseeing a "witch hunt" against him.

"I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director!" Trump said on Twitter, calling the probe into him a "Witch Hunt."

I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt — Donald J. Trump (@realDonaldTrump) June 16, 2017

The President's tweet sparked immediate speculation about the future of the official, Rod Rosenstein, who wrote a memo recommending Comey be ousted and also later approved the appointment of a special counsel -- Robert Mueller -- to lead the Russia probe.

A person familiar with Trump's tweet said the President was referencing news reports that he is under investigation and was not indicating that he's been personally informed by the special counsel that he is a target of the probe.

The tweet represented a remarkable show of frustration by a serving President, who is making no secret of his emotions as an investigation that started out as an effort to understand Russian meddling in the election appears to be moving ever closer towards his inner circle and narrowing in on his own conduct.