Ellen Weintraub, who has served as a Democratic member of the FEC since 2002, posted a letter signed by Donald Trump on social media that said she was “hereby removed as a Member of the Federal Election Commission, effective immediately.”

Weintraub, who is currently chairperson of the FEC, questioned the legal validity of the move and signaled her intent to fight the removal.

Her term expired in 2007, but under federal law, she is allowed to remain a commissioner until a replacement is confirmed by the Senate.

Weintraub voted to investigate the president over allegations involving violating rules barring coordination between Trump’s campaign and allied super PACs and accusations that Russia tried to influence the outcome of the 2016 election.

She also voted to investigate Trump for promoting some of his businesses, including hotels and golf courses, during the 2016 campaign, including at rallies.