Whether a Massachusetts judge acted corruptly when she allegedly obstructed a U.S. Immigration and Customs Enforcement arrest is at the center of a fight over an attempt to get her charges dismissed.

A panel for the U.S. Court of Appeals for the First Circuit heard arguments Monday in an appeal of a lower court’s denial of a motion to dismiss charges against Newton District Court Judge Shelley Joseph, who, along with former Trial Court Officer Wesley MacGregor, is accused of helping an undocumented man in her courtroom evade federal immigration agents in 2018.