Former New York City mayor Rudolph Giuliani ripped into the FBI's early investigation of Hillary Clinton's private email server Friday night, calling it a "sham" and saying the bureau did "a completely irresponsible" job.

"If you read the [summary] of her interview, it’s absurd. The FBI agent doing that [summary] didn’t follow up on anything," Giuliani told Fox News' Sean Hannity on "Hannity." "In other words, she was questioned as follows 'Did you do the murder?' 'No.' 'Thank you.' And they walked out.

The FBI is investigating whether there is classified information in new emails uncovered during the sexting investigation of disgraced former congressman Anthony Weiner, the estranged husband of one of Hillary Clinton's closest aides.

FBI Director James Comey had announced in July that "no reasonable prosecutor" would seek an indictment against Clinton for mishandling classified information while secretary of state, though he noted that she had been "extremely careless." He notified congressional leaders of the new turn in the investigation Friday, though he did not reveal details of the probe.

"The reality is, the report that Comey gave to us [in July] before he came to the conclusion that she shouldn’t be prosecuted was a report that any prosecutor would have taken before a grand jury, probably got an indictment, and the evidence of intent is overwhelming," said Giuliani, a former federal prosecutor. "You don’t interview someone on a Saturday and put out a complete report on a Tuesday, unless the report was written before you interviewed her."

"The cover-up is worse than the crime," Giuliani added. "Although in this particular case, the crime was pretty bad, exposing national security information to countries we know can take it from us ... And for that, you shouldn’t be allowed to get off.