Former New York City mayor and lawyer Rudy Giuliani -- one of President Donald Trump's most loyal sycophants -- finds himself the target of an FBI probe for spreading Russian misinformation a few days after his only daughter urged Americans to vote Democrat Joe Biden and Kamala Harris into office.

He also has to contend with a claim by Michael Cohen, who was once Trump's personal lawyer and fixer, he's easily duped by Russians into spreading lies about Biden because "Rudy is drunk all the time."

The FBI on Saturday continued investigating whether emails published by a pro-Trump New York City tabloid and furnished by Giuliani are part of an influence operation hatched by the Russians to damage Biden and boost Trump.

FBI suspicions Giuliani might either be a witting or unwitting Russian agent seem to confirm an earlier warning by top U.S. intelligence officials Giuliani remains the target of an ongoing Russian influence operation.

The intelligence leaders said their assessment of Giuliani was based on information that included intercepted messages confirming Giuliani was in contact with either Russian spies or people linked to Russian intelligence.

Analysts said Giuliani's case underscores the risk he poses to the White House, especially now that Trump is pulling all the strings he can to stave-off almost certain defeat on November 3.

National security adviser Robert O'Brien had also warned Trump -- to no avail -- that information Giuliani brought back from Ukraine should be considered contaminated by Russia. Part of this information falsely accusing Biden of corruption was published by the pro-Trump tabloid last week.

Instead of dismissing the Russian information from Giuliani, Trump has used it as a cudgel to attack Biden in the final weeks of the campaign.

On Saturday, Cohen flat out accused Giuliani of being an inveterate drunk easily manipulated by the Russians. Asked on MSNBC if he thinks Giuliani is being used as a tool and a hack of the Russians, Cohen replied in the affirmative.

"Of course it's wrong and the answer is yes," replied Cohen. "Rudy is being played by the Russians.

"He's 100 percent susceptible to being used by the Russians because ... the disinformation, he runs right back to President Trump like a child running to a parent: (saying) 'Look what I have. Look what I have.'"

Cohen said Trump "speaks and behaves like the mob boss" and that "he's using his soldier (Giuliani)", to dig up dirt on Biden.

"The problem here is that Rudy isn't a soldier," said Cohen. "Rudy is -- Rudy is drunk all the time, which is a big problem and that's what makes him susceptible because his faculties are gone. He behaves crazy."

Cohen said he's personally seen Giuliani "drink to the point like he's a high school drunk." This behavior "makes him susceptible" to Russian manipulation.

Both these embarrassing episodes came after Giuliani's only daughter, Caroline Rose, blasted him harshly in a personal opinion piece published in Vanity Fair on Thursday.

Giuliani's 31-year-old filmmaker daughter assailed her father as a Trump "yes-man" and a crony who enabled Trump's "reign of terror" which stoked "the injustice that already permeated our society, taking it to dramatically new, Bond-villain heights."

She said corruption starts with yes-men "who create an echo chamber of lies and subservience to maintain their proximity to power. We've seen this ad nauseam with Trump and his cadre of high-level sycophants (the ones who weren't convicted, anyway)."

She wholeheartedly endorsed Biden and Harris and urged Americans to elect the Democratic ticket into office in November.

"I may not be able to change my father's mind, but together, we can vote this toxic administration out of office," she said. "It's taken persistence and nerve to find my voice in politics, and I'm using it now to ask you to stand with me in the fight to end Donald Trump's reign of terror."