Fired FBI Director James Comey on Tuesday said it was “confusing” to him that special counsel Robert Mueller’s investigation into alleged collusion between the 2016 Trump campaign and Russia did not conclude whether President Donald Trump obstructed justice.

“The part that’s confusing is I can’t quite understand what’s going on with the obstruction stuff,” Comey told an audience at the Belk Theatre in Charlotte, North Carolina, reported 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,” the longtime law enforcement official turned Trump critic added.

Attorney General William Barr and Deputy Attorney General Rod Rosenstein opted not to pursue obstruction of justice charges against the president after the special counsel said it would not make a determination on the process crime. The Justice Department’s four-page summary of Mueller’s findings released Sunday said the 2016 Trump campaign was found not to have colluded with the Russian government during the last election.

“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,” said Comey. “Obstruction crimes matter without regard to what you prove about the underlying crime.”

Comey, who has praised Mueller as “one of the finest public servants this nation has ever seen,” said he was relieved the special counsel was able to complete the probe. “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,” he 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.”

In a New York Times opinion-editorial last week, Comey wrote that he did not know what Mueller’s reports would conclude, nor did he care so long as the probe was conducted properly. “I have no idea whether the special counsel will conclude that Mr. Trump knowingly conspired with the Russians in connection with the 2016 election or that he obstructed justice with the required corrupt intent,” the veteran Deep Stater said. “I also don’t care. I care only that the work be done, well and completely.”

A Justice Department official said Tuesday Barr would release details of the investigation viewable by the public in “weeks not months.”