Former Democratic National Committee (DNC) interim chairwoman Donna Brazile writes in a new book that it “broke my heart” when she discovered evidence that she said showed Hillary Clinton’s campaign fixed the Democratic nomination system in her favor.

In an excerpt from “Hacks: The Inside Story of the Break-ins and Breakdowns that Put Donald Trump in the White House” that was provided to Politico, Brazile explains how she was tasked with investigating the DNC after hacked emails suggested the Clinton campaign fixed the nomination.

“By September 7, the day I called Bernie, I had found my proof and it broke my heart,” Brazile wrote, referring to Clinton’s challenger, Sen. Bernie Sanders (I-Vt.).

Brazile described an agreement between the Clinton campaign, the DNC, and Clinton’s joint fundraising committee with the committee that said the campaign would “control the party’s finances, strategy, and all the money raised.” The arrangement was made to financially help the party, which was in significant debt following the 2012 reelection campaign of former President Barack Obama, she added.

“The campaign had the DNC on life support, giving it money every month to meet its basic expenses, while the campaign was using the party as a fund-raising clearing house,” Brazile wrote.

Brazile noted that the agreement was signed in August of 2015, effectively giving Clinton control of the party almost one year before she secured the nomination.

“The funding arrangement … was not illegal, but it sure looked unethical,” Brazile wrote.

“If the fight had been fair, one campaign would not have control of the party before the voters had decided which one they wanted to lead. This was not a criminal act, but as I saw it, it compromised the party’s integrity.”

Brazile’s revelations add to criticism from supporters of Sanders, who ran an unsuccessful insurgent campaign against Clinton in the Democratic primary.

Brazil also criticized Rep. Debbie Wasserman Schultz (D-Fla.), who helmed the DNC as chairwoman before Brazile assumed the role of interim chair, as “not a very good manager” who was not “very interested in controlling the party.”

“The party chair usually shrinks the staff between presidential election campaigns, but Debbie had chosen not to do that. She had stuck lots of consultants on the DNC payroll, and Obama’s consultants were being financed by the DNC, too,” Brazile wrote