Bernie Sanders’ campaign fired off a letter to the Democratic National Committee questioning “serious apparent violations” of campaign finance laws by Hillary Clinton, calling into question to the joint fundraising deal between her campaign and the DNC.

Over the course of the Democratic primary, the Clinton campaign has held numerous high-dollar fundraisers bringing in individual donations as high as $353,400 to the Hillary Victory Fund, a number over 130 times the $2,700 limit that applies to individual campaign contributions.