The former Federal Bureau of Investigation director is planning a series of media appearances to promote his book, "A Higher Loyalty: Truth, Lies, and Leadership", starting with an ABC News interview airing Sunday evening at 10 p.m., ET. "I think he's morally unfit to be president", Mr Comey replied.
Mueller is investigating Russian interference in the 2016 election and any potential ties between Trump campaign associates and Russia.
Mr Comey said he thought it was possible the Russians had compromising information on Trump and that he treated women like "pieces of meat". And that's not a policy statement.
He added: "He [Trump] is morally unfit to be president".
"A Higher Loyalty" won't be formally released until Tuesday, but explosive details have already spilled out into the media. Titled 'A Higher Loyalty: Truth, Lies, and Leadership, ' his book paints a predictably unflattering picture of Trump, who fired Comey in May 2017 over his handling of the FBI investigation into Hillary Clinton's use of a private server for classified emails during her time as secretary of state.
On Sunday, Trump unloaded a series of nasty tweets about Comey, and called him "slippery", and a "slime ball" and predicted that he would be remembered "as the Worst FBI Director in history, by far!"
While Trump bore the brunt of his criticism, Comey also took aim at others - including Deputy Attorney General Rod J. Rosenstein, whom Trump has been contemplating removing from his post. That's because, he says in the interview, the U.S. leader puts personal loyalty and his family above the interests of the state. He says Schumer had tears in his eyes as he acknowledged the dilemma Comey had grappled with during the election. The FBI has long tried to operate as an independent law enforcement agency. There's no way I'd let people pee on each other around me.' And that me caught me so much by surprise I actually let out an audible laugh and - 'cause it was just one of those - I was startled by it.
Facebook shows dangers of giving up our privacy
This conversation is relevant because Zuckerberg was asked twice by congress about Facebook potentially offering subscriptions. Democrats and Republicans alike repeatedly cut off Zuckerberg, who appeared less composed than he did at the Tuesday hearing.
"And he interrupted very defensively and started talking about it, you know, 'Do I look like a guy who needs hookers?'"
In a Quinnipiac University poll published last month, 84 percent of Republicans approved of Trump's job performance, and only 31 percent said he is not a good role model for children.
The claims prompted Trump to hurl a brand new set of insults at Comey earlier on Sunday. I can not say that (Trump is not subject to Russian blackmail). Trump cited the memo in firing Comey, and Comey said he came to believe Rosenstein was "part of the family now". It did not become publicly known until after the 2016 presidential election. "People in this country need to stand up and go to the voting booth and vote their values", he said.
"Tonight, in honor of upcoming tax day, we thought we'd give you just a glimpse of the lengths that companies will go to to legally avoid paying taxes, both", John Oliver said on Sunday's Last Week Tonight.
Comey says he was just as surprised as everyone else that he was sacked in the middle of an important ongoing investigation: "I thought it's insane to fire me".
Because of that Comey said he believed it "was important that we try to understand [the dossier], and see what could we verify".
The Trump administration, with the support of the Republican National Committee, has mounted a campaign to discredit Comey amid the release of his book. While Trump's "initial denial seemed reasonable", Comey says that "when someone constantly brings up to deny something you're not asking about, that's an interesting fact".