A trove of emails released by WikiLeaks on Friday revealed that senior officials at the Democratic National Convention criticized and poked fun at Sen. Bernie Sanders (I-VT) during the primary race.

In the nearly 20,000 searchable emails sent and received by Communications Director Luis Miranda, Finance Chief of Staff Scott Comer, and other top DNC operatives, Sanders’ campaign was dismissed as amateurish and ill-fated. The emails seem to back up the charge that DNC officials, including chairwoman Rep. Debbie Wasserman Schultz (D-FL), favored Hillary Clinton. The Vermont senator and his top aides repeatedly made this claim during the primaries, with campaign manager Jeff Weaver even alleging that Wasserman Schultz was working against Sanders “for personal reasons.”

In one email exchange, Miranda asked Wasserman Schultz if they should call CNN to complain about Sanders’ on-air claim that he would replace her if elected.

“Do you all think it’s worth highlighting for CNN that her term ends the day after the inauguration, when a new D.N.C. Chair is elected anyway?” he asked.

“This is a silly story,” Wasserman Schultz replied. “He isn’t going to be president.”

WikiLeaks did not reveal the source of the leak. Last month, however, the DNC announced that Russian hackers gained access to its email system to steal opposition research on Donald Trump.

Sanders, who has not yet publicly responded to the email leak, endorsed Clinton’s campaign earlier in July.

The leaks come at an awkward time given the start of the Democratic National Convention next week, where Sanders is scheduled to speak.

WikLeaks said that this release was part one of the group’s new “Hillary Leaks series.”