One of Donald Trump’s co-defendants in the Georgia election subversion case filed a motion Monday to disqualify Fulton County District Attorney Fani Willis from the case on the basis of claims she had an improper romantic relationship with a prosecutor she put on the case.

The motion from former Trump campaign staff member Michael Roman accuses Willis of “an act to defraud the public of honest services” because of the alleged secret romantic relationship she had with Nathan Wade, a top prosecutor she brought on to lead the investigation against Trump and his 18 co-defendants in the criminal conspiracy case.

According to Roman’s claims, Willis was romantically linked to Wade before she brought him aboard as part of a “self-serving arrangement” that financially benefited them both.

“Willis has benefitted substantially and directly, and continues to benefit, from this litigation because Wade is being paid hundreds of thousands of dollars to prosecute this case on her behalf,” the motion claims. “In turn, Wade is taking Willis on, and paying for vacations across the world with money he is being paid by the Fulton County taxpayers and authorized solely by Willis.”

Roman’s filing provides no concrete evidence of a relationship between Willis and Wade, saying only that “sources close to both [Wade] and the district attorney have confirmed they had an ongoing, personal relationship.”

In the event that Willis is removed from the case, it would be up to Georgia Attorney General Chris Carr, a Republican, to appoint another district attorney in the state to take over the proceedings.

Willis’ office told ABC News that it would respond to Monday’s motion “through appropriate court filings.”

The Fulton County district attorney has been the target of widespread racist abuse following her decision to indict Trump. In an interview on Revolt in September, she said: “I’ve been called the N-word so many times, I don’t even think I hear it anymore,” adding that she and her family members have been doxxed by people opposed to her handling of the prosecution.

Her case against Roman accuses him of being one of the key operatives in the Trump campaign’s attempt to use a slate of fake electors in Georgia who would assert that Trump had won the presidential vote in the state. He has a history of peddling Trump’s stolen election claims, falsely tweeting during the 2020 election that “TRUMP observers are being blocked entry to all of the satellite voting locations in Philly!!” and asking, “What are they hiding?”

Roman’s filing comes on the last day parties in the case are allowed to file pre-trial motions. Earlier on Monday, Trump’s attorneys filed a motion claiming he had presidential immunity in the 13 charges Willis brought against him.