New York Attorney General Letitia James is challenging the legitimacy of the acting U.S. attorney in Albany as she pushes back against the Trump administration's investigation of cases she brought against the president and the National Rifle Association, according to court documents unsealed Friday. James in August filed a motion to block subpoenas issued by acting U.S. Attorney John Sarcone for records related to the legal actions, claiming the Justice Department's probe of the cases was retaliatory.