Former surrogates of Sen. Bernie Sanders, I-Vt., from the 2016 campaign are fuming about the Democratic National Committee in response to Donna Brazile's disclosure of "proof" that the Hillary Clinton campaign took over the DNC's finances and operations in an effort to tip the scales in Clinton's favor for the party's presidential nomination in 2016.

With many noting they have been crying foul since the primary, multiple liberal figures in the Democratic Party took the opportunity issue a fresh cadre of demands to change the DNC, which earlier this year picked an Establishment-favorite, Tom Perez, to lead over the liberals' preferred candidate, Rep. Keith Ellison.

"Today we heard from Donna Brazile that what many suspected for a long time, is actually true: the DNC secretly chose their nominee over a year before the primary elections even occurred, turning over DNC control to the Clinton campaign," said Rep. Tulsi Gabbard, D-Hawaii, a former DNC vice chairman. Gabbard, declared the 2016 primary "rigged," resigned from the DNC in February 2016 in order to endorse Sanders.

Gabbard has been pushing a people to sign a petition "demanding the DNC establish accountability measures in their decision-making processes, eliminate undemocratic superdelegates, and ensure open or same day registration primaries to ensure we return to a party structure that serves the people."

Brazile's "proof," shown in an excerpt from her upcoming book published by Politico, revealed an agreement she discovered between two Clinton campaign funds and the DNC, in which money would be exchanged for control over DNC finances and strategy. She also said the move was "unethical."

The DNC did not, however, escape controversy at the time, as then-Chairwoman Rep. Debbie Wasserman Schultz of Florida exited her role at the DNC after emails published by WikiLeaks showed she and party officials conspiring to tip the Democratic primary in Clinton's favor. This led to Brazile's entry as interim head until the February election.

Despite the shakeup last summer and calls for unity around Clinton's nomination, Gabbard said the DNC still needs to reform moving forward.

Another former Sanders surrogate, Nina Turner echoed that sentiment, calling for an effort to "restore the faith and credibility of the Democratic Party."

She clashed with Democratic strategist Hilary Rosen on CNN, who said Democrats “could not be stupider” for trying to re-litigate the Democratic Primary. Turner shot back that the DNC "lacks accountability and transparency. Period."

"Statements like you’re making doesn’t help," she said. "People are hurt by this revelation. And this does not help. So to cover it up doesn’t help. So don’t go there with that. The fact of the matter remains the way the system was conducted, the DNC did not follow its own bylaws. And so if we’re going to have some truth talk here, let’s talk about reform and let’s talk about unity.”

Sen. Elizabeth Warren, D-Mass., who is often compared to Sanders in progressive circles and is seen as a potential 2020 contender, was more reserved than some of the former Sanders surrogates, but made a shocking admission Thursday when she said that, "yes," she believes the DNC was rigged to favor Clinton.

In response, Turner tweeted, "I guess Senator Warren is a sexist Berniebro now too." "Bernie Bros" were a label given to ardent Sanders supporters during the campaign who sometimes harassed Clinton backers and anyone who spoke negatively of Sanders and were criticized for misogynistic behavior online.

Another leading former surrogate of Sanders, rapper Killer Mike, tweeted in reply, "Like My Grandma Wud say 'Truth comes out in the rinse, baby.'"

The list of outraged Democrats goes on, as Mediaite points out.

It's yet to be seen whether the DNC adheres to pressure from the liberal-wing to change. After all, the organization only recently went through a shakeup in which several longtime officials were removed from their posts in a sweep that was largely seen as a rebuke the the so-called progressive-wing of the party.

Furthermore, Perez, the new chairman, brushed off Brazile's bombshell on Thursday. "Hey, we're moving forward," he said when asked about it. "We're building, you know, I've been asked that question a number of times since I started."

On the same day Politico reported that the DNC fired its top fundraiser amid sagging fundraising numbers.

Sanders has so far maintained his silence on the matter, but he has another high-profile defender in President Trump, who told Fox News' Laura Ingraham that he is no fan of Sanders', but argued the DNC was "very unfair" to him.

He went further in a pair of tweets in which he said there was "real collusion" between the DNC and Clinton's team. Trump himself is being investigated for possible collusion with the Russians during the 2016 campaign.