Rep. Debbie Wasserman Schultz (D-Fla.) privately lashed out about a top Bernie SandersBernie SandersThe Hill’s Whip List: Where Dems stand on Trump’s Supreme Court nominee Friends, foes spar in fight on Trump’s Supreme Court nominee Sanders: 'What do the Russians have on Mr. Trump?' MORE campaign aide, calling him a "damn liar" in an email earlier this year.
"Damn liar. Particularly scummy that he barely acknowledges the violent and threatening behavior that occurred," Wasserman Schultz, the head of the Democratic National Committee (DNC), wrote to DNC staffers in an email dated from May 17, shortly after a contentious Nevada convention fight between supporters of Sanders and Hillary ClintonHillary Rodham ClintonDem rep: 'We must pause the entire Trump agenda' until Russia investigation complete New England Patriots to visit White House on April 19 More than ever, Justice must demand a special prosecutor for Trump-Russia probe MORE over delegates.
Wasserman Schultz in her email was referring to Sanders campaign manager Jeff Weaver, who during a CNN appearance had said the Nevada state party hadn't been fair.
"It is not a reflection of all Democrats in Nevada, but the party hierarchy, there’s a lot of problems there," he told CNN's Jake Tapper at the time. "We have interacted with state parties all across the country. And some are more fair than others. Some are, I have to say, some are extremely fair. It just happens in Nevada not to be the case."
Wasserman Schultz also balsted Weaver in a separate email in May, calling him "an ASS" for saying Sanders would stay in the race until the convention.
The leaked Wasserman Schultz emails come days ahead of the party's convention in Philadelphia next week, when Democrats are expected to formally name Clinton as the nominee. Sanders is scheduled to speak Monday, in what Clinton supporters hope will help unite the party going into November.
But the emails could reopen a long simmering feud between the DNC and the Sanders campaign, which claimed for months that the party and Wasserman Schultz were biased in favor of the Clinton campaign throughout the primary.
Sanders supporters have called for Wasserman Schultz to be replaced. Sanders also endorsed her primary opponent, but CNN reported earlier this month that she was safe in her spot atop the DNC until at the November elections.
Many emails highlight the tensions between the two camps and some show DNC officials discussing how to undermine Sanders's presidential bid.
Comments from Sanders in April about the state of the race and how he didn't believe the party had been "fair" to him also earned a sharp rebuke from Wasserman Schultz.
"Spoken like someone who has never been a member of the Democratic Party and has no understanding of what we do," she wrote in an internal email about the Independent Vermont senator.
In a separate email in early May, Mark Paustenbach, a Democratic spokesman, floated pushing the story that Sanders "never ever had his act together, that his campaign was a mess."
"Specifically, DWS had to call Bernie directly in order to get the campaign to do things because they'd either ignored or forgotten to something critical," he added in the email.
This story was updated at 3:16 p.m.