New Orleans (AP) — Lawyers for the district attorney in New Orleans are asking a federal appeals court to end a lawsuit centered on his office having used fake subpoenas to coerce uncooperative witnesses.

Attorneys representing Leon Cannizzaro and some of his staff were set to argue Wednesday that the prosecutors are legally immune from claims made in a 2017 lawsuit by criminal justice advocates. The case is before a three-judge panel of the 5th U.S. Circuit Court of Appeals.

Last year, a federal judge agreed that prosecutors had immunity from some of the claims in the lawsuit. But U.S. District Judge Jane Triche Milazzo allowed much of the suit to continue, saying some of the claims “shock the conscience.”

The lawsuit was filed by the American Civil Liberties Union and the Civil Rights Corps after the online news outlet The Lens exposed prosecutors’ use of documents labeled “subpoena” that had not been approved by a judge. Cannizzaro has said the practice ended in 2017.

Also challenged in the suit are aspects of the district attorney’s office’s use of “material witness” warrants that can lead to the jailing of uncooperative witnesses.