Lawyers for former President Donald Trump were heading back to a New York appeals court on Wednesday, with their third legal challenge involving his impending criminal trial in three days.

The court docket for the state Appellate Division shows Trump’s attorneys filed the challenge as a lawsuit invoking a provision of New York law known as Article 78. Article 78 challenges allow litigants, whether in ongoing litigation or otherwise, to seek relief from allegedly unlawful state or local government action.

The documents were filed under seal. The Manhattan district attorney’s office, which is prosecuting the case, said it involved Judge Juan Merchan‘s refusal to step aside from presiding over the case. Attorneys for the former president have pointed to the judge’s daughter’s employment at a political firm that did work for President Joe Biden’s 2020 campaign as evidence of his “significant conflicts.”

The trial is scheduled to begin Monday.

A hearing on the challenge was expected to take place later Wednesday.

On Monday, Trump filed a separate Article 78 petition with the Appellate Division seeking to halt the trial by arguing he can’t get a fair trial in Manhattan. A judge denied that request Monday, and a separate judge denied his request to delay the trial on Tuesday while he appeals the gag order Merchan imposed on him as “unconstitutional.”

This article was originally published on NBCNews.com