Former Clinton campaign manager Robby Mook testified Friday that then-Democratic presidential nominee Hillary Clinton approved the dissemination of materials alleging a covert communications channel between the Trump Organization and Russia’s Alfa Bank to the media, despite campaign officials not being "totally confident" in the legitimacy of the data.

Former FBI General Counsel James Baker testified Thursday that the bureau investigated the data alleging a Trump connection to the Kremlin-linked bank, and found that "there was nothing there."

Mook was called to the stand for testimony by Michael Sussmann’s defense Friday.

During cross-examination by government prosecutor Andrew DeFillippis Friday, Mook was asked about the campaign’s understanding of the Alfa Bank allegations against Trump and whether they planned to release the data to the media.

Mook said he was first briefed about the Alfa Bank issue by campaign general counsel Marc Elias, who at the time was a partner at lawfirm Perkins Coie.

Mook testified that he was told that the data had come from "people that had expertise in this sort of matter."

Mook said the campaign was not totally confident in the legitimacy of the data, but had hoped to give the information to a reporter who could further "run it down" to determine if it was "accurate" or "substantive."

Robby Mook, Campaign Manager for U.S. Democratic presidential nominee Hillary Clinton, and Communications Director Jen Palmieri (L), talk to reporters onboard the campaign plane enroute to Cedar Rapids, Iowa, U.S. October 28, 2016.

He also said he discussed whether to give the information to a reporter with senior campaign officials, including campaign chairman John Podesta, senior policy advisor, now White House National Security Adviser Jake Sullivan, and communications director Jennifer Palmieri.

"I discussed it with Hillary as well," Mook said.

"I don’t remember the substance of the conversation, but notionally, the discussion was, hey, we have this and we want to share it with a reporter," Mook said.

The government asked Mook if Clinton approved "the dissemination" of the data to the media.

"She agreed," Mook testified.

Mook later said he "can't recall the exact sequence of events," when asked if he shared the idea to give the Trump-Alfa Bank allegations to the media with Clinton before or after the decision was made.

"All I remember is that she agreed with the decision," Mook testified.

Sussmann has been charged with making a false statement to the FBI when he told Baker in September 2016, less than two months before the presidential election, that he was not doing work "for any client" when he requested and attended a meeting in which he presented "purported data and ‘white papers’ that allegedly demonstrated a covert communicates channel" between the Trump Organization and Alfa Bank, which has ties to the Kremlin.

Attorney Michael Sussmann departs the U.S. Federal Courthouse after opening arguments in his trial, where Special Counsel John Durham is prosecuting Sussmann on charges that he lied to the FBI) while providing information about later discredited allegations of communications between the 2016 presidential campaign of former President Donald Trump and Russia, in Washington, May 17, 2022.

Durham’s team alleges Sussmann was, in fact, doing work for two clients: the Hillary Clinton campaign and a technology executive, Rodney Joffe. Following the meeting with Baker, Sussmann billed the Hillary Clinton campaign for his work.

Sussmann has pleaded not guilty to the charge.

Mook, earlier in questioning from the defense, was asked whether he or anyone on the Clinton campaign approved or gave Sussmann permission to bring the allegations to the FBI, to which he said: "No."

Later, the defense further questioned Mook, asking if Hillary Clinton herself approved Sussmann going to the FBI.

"I'm not aware," Mook testified.

When asked again, he said: "I don't know…I don't know why she would."

The government, in its opening statement Tuesday, argued that Sussmann's delivery of the Trump-Alfa Bank allegations to the FBI was part of the Clinton campaign's plan to create an "October surprise" against then-candidate Donald Trump.

The government moved to admit a tweet from Clinton dated Oct. 31, 2016 as evidence, despite U.S. District Judge Christopher Cooper ruling last month that the court would exclude that tweet as hearsay.

Cooper, Friday, granted the government’s motion to admit the Clinton tweet, which stated:

"Computer scientists have apparently uncovered a covert server linking the Trump Organization to a Russian-based bank."

Clinton also shared a statement from Jake Sullivan, which stated: "This could be the most direct link yet between Donald Trump and Moscow. Computer scientists have uncovered a covert server linking the Trump Organization to a Russian-based bank."

Sullivan said the "secret hotline may be the key to unlocking the mystery of Trump’s ties to Russia."

"This line of communication may help explain Trump’s bizarre adoration of Vladimir Putin and endorsement of so many pro-Kremlin positions throughout this campaign," Sullivan's 2016 statement continued. "It raises even more troubling questions in light of Russia’s masterminding of hacking efforts that are clearly intended to hurt Hillary Clinton’s campaign."

Sullivan added that they "can only assume federal authorities will now explore this direct connection between Trump and Russia as part of their existing probe into Russia’s meddling in our elections."

When asked for the definition of an "October surprise" Friday, Mook testified that it is "the idea that you have a devastating piece of opposition research and drop it on candidate so the candidate doesn't have time to respond or recover from it and, as a result, loses the election."

Hillary Clinton pauses while speaking in New York, Wednesday, Nov. 9, 2016, where she conceded her defeat to Republican Donald Trump after the hard-fought presidential election

When pressed to identify the date of the Clinton tweet for the jury, Mook stated: "Oct. 31, 2016."

Mook defended the tweet saying: "I did not see it as some sort of silver bullet and I don't think that others on the campaign did either."

As for the Trump-Alfa Bank allegations in general, Mook said: "We thought this was highly suspect and, if it was true, we wanted the American public to know about it for sure."

Mook again called the data "certainly alarming and suspicious."

Meanwhile, Baker testified Thursday that the FBI began an investigation into the Trump-Alfa Bank allegations, which lasted "several weeks, maybe a month, maybe a month and a half."

"We concluded there was no substance," Baker testified. "We couldn’t confirm it. We could not confirm there was a surreptitious communications channel."

Baker added: "There was nothing there."

In testimony on Tuesday afternoon, FBI Special Agent Scott Hellman also said the data revealing the alleged covert communications channel between Trump and Russia that Sussmann brought to the FBI turned out to be untrue, and said he did not agree with the narrative.

Hellman testified that whoever drafted the narrative describing the DNS data was "5150," and clarified on the stand that meant he believed the individual who came to the conclusions "was suffering from some mental disability."

Mook’s testimony revealing Clinton approved the plan to share the Trump-Alfa Bank allegations with the media comes after Fox News first reported that the CIA, dating back to July 2016, had information of Clinton’s "approval of a plan" to tie Trump to Russia "as a means of distracting the public from her use of a private email server."

Fox News obtained declassified notes from then-CIA Director John Brennan after briefing then-President Obama on July 28, 2016, memorializing Clinton’s purported "proposal from one of her foreign policy advisers to vilify Donald Trump by stirring up a scandal claiming interference by the Russian security service."

The information was properly forwarded to the FBI in an Counterintelligence Operational Lead (CIOL), and to the attention of then-FBI Director James Comey and then-Deputy Assistant Director of Counterintelligence Peter Strzok on Sept. 9, 2016.

"The following information is provided for the exclusive use of your bureau for background investigative action or lead purposes as appropriate," the 2016 CIA memo to Comey and Strzok stated.

"Per FBI verbal request, CIA provides the below examples of information the CROSSFIRE HURRICANE fusion cell has gleaned to date," the memo continued. "An exchange [REDACTED] discussing US presidential candidate Hillary Clinton’s approval of a plan concerning US presidential candidate Donald Trump and Russian hackers hampering US elections as a means of distracting the public from her use of a private email server."

The memo was heavily redacted.

Fox News first reported that those materials were provided to the Justice Department by former Director of National Intelligence John Ratcliffe in 2020 to support Special Counsel John Durham’s investigation into the origins of the Trump-Russia probe.