Fired FBI Director James Comey says he can't 'quite understand' why special counsel Robert Mueller let Donald Trump's attorney general decide whether the president obstructed justice.

Comey said Tuesday evening at a Queens University, in Charlotte, North Carolina, event that he found it baffling that Mueller left it up to the president's political appointees - Attorney General William Barr and Deputy Attorney General Rod Rosenstein - to determine whether to prosecute Trump.

'The part that's confusing is, I can't quite understand what's going on with the obstruction stuff,' Comey said at the event, according to NBC News.

'And I have great faith in Bob Mueller, but I just can't tell from the letter why didn't he decide these questions when the entire rationale for a special counsel is to make sure the politicals aren't making the key charging decisions.'

Fired FBI Director James Comey says he can't 'quite understand' why special counsel Robert Mueller let Donald Trump's attorney general decide whether the president obstructed justice

Comey said Tuesday evening at a Queens University event that he found it baffling that Mueller left it up to the president's political appointees to determine whether to prosecute Donald Trump. Attorney General William Barr (right) opted not to

Mueller said in a letter to lawmakers that he could find no evidence to indicate that Trump is guilty of crimes

The former law enforcement official who Trump fired in May of 2017 is at the center of the accusation that the president obstructed justice.

Theories have abounded for years that Trump booted Comey to cover up his campaign's crimes, his business and personal connections to Russia, protect his children or hide other unethical behavior he didn't want the Department of Justice to uncover.

Mueller said in a letter to lawmakers that he could find no evidence to indicate that Trump is guilty of crimes.

He did not bring charges against anyone in Trump's inner circle or the president's children, either, which the president's attorneys have said is proof positive that the president has no motivation to impede the investigation.

Some Democrats are convinced that a broader investigation of the president's finances and businesses would reveal that Trump broke the law. The special counsel investigation was narrowly-tailored to a Russian-led conspiracy to disrupt the 2016 presidential election.

In a letter presenting Mueller's findings, new Attorney General Barr said it fell to him to decide whether Trump obstructed justice based on the special counsel's report and the underlying evidence.

Barr said he consulted with Rosenstein, and they determined together that the sitting president had no motive to obstruct the investigation that proved he wasn't guilty of collusion.

He said that 'to obtain and sustain an obstruction conviction, the government would need to prove beyond a reasonable doubt that a person, acting with corrupt intent, engaged in obstructive conduct,' and he could not do that.

Comey said Tuesday night, in his first public remarks since the special counsel filed his final report, that he found Barr's reasoning 'really confusing' and would not necessarily have reached the same conclusion.

'The notion that obstruction cases are somehow undermined by the absence of proof of an underlying crime, that is not my experience in 40 years of doing this nor is it the Department of Justice's tradition. Obstruction crimes matter without regard to what you prove about the underlying crime,' Comey said.

Despite the president assailing him as a 'bad' and 'corrupt' cop, he insisted he wasn't hoping that Trump would get caught red handed.

'The good part is that the special counsel was allowed to finish his work and reached a conclusion; that's very, very important to this country,' Comey said. 'The Russians really did massively interfere with the 2016 election with the goal of damaging one candidate and helping the other. That was not a hoax. That was a real thing.'

