Orleans Parish District Attorney Leon A. Cannizzaro, Jr., in City Council Chambers on Wednesday, Sept. 20, 2017.

New Orleans prosecutors have asked a federal judge to dismiss a far-reaching lawsuit brought by civil rights groups against the Orleans Parish District Attorney’s Office over its use of aggressive tactics like jailing witnesses and issuing bogus subpoenas.

The DA’s Office said in a March 1 filing that many of the allegations in the lawsuit were false and that U.S. Supreme Court rulings provide prosecutors with a broad shield from legal liability.

U.S. District Judge Jane Triche Milazzo has yet to rule on the motion to toss out the case.

Meanwhile, civil rights groups have filed an amended version of their October lawsuit against DA Leon Cannizzaro, pointing to new evidence that his top lieutenant told prosecutors to serve bogus subpoenas on reluctant witnesses.

The DA's Office served those “subpoenas” on witnesses and crime victims for years, despite the fact that they did not have a judge’s signature and had no legal value. Prosecutors say they stopped using them in April.

However, prosecutors continue to obtain material witness warrants when they can persuade a judge that key witnesses, including crime victims, will not show up for trial unless they are put in jail. State law allows for material witness warrants, but the lawsuit claims that prosecutors have misled judges into issuing them.

The district attorney’s motion to dismiss the lawsuit filed by the American Civil Liberties Union and the Civil Rights Corps takes issue with almost all its factual allegations as well as its legal foundations.

The contested claims start with the lead plaintiff, Renata Singleton, who was jailed for five days on a material witness warrant in connection with a domestic violence case.

Singleton had accused her ex-boyfriend of breaking her phone during a scuffle. She said that when she told prosecutors she did not want to pursue the charges, they sent her two bogus subpoenas telling her to come to the DA’s Office. The office then jailed her on a $100,000 bond by citing the bogus subpoenas in an application to a judge for a material witness warrant, she said.

However, prosecutors claim the lawsuit told only part of the story. Singleton failed to show up for a trial date before prosecutors had her arrested, they say.

“The suggestion that Ms. Singleton was arrested merely because she would not speak privately with prosecutors is simply false,” the DA’s Office said.

Prosecutors reject a host of other claims in the lawsuit. They say that another crime victim was subject to a court-ordered subpoena and not a bogus one, that one woman also missed a trial date before she was jailed, and that a shooting victim told prosecutors he would show up in court only if he was arrested.

“It is indeed ironic that a lawsuit accusing the defendants of ‘mak(ing) false statements’ … relies so heavily on false and misleading depictions of the underlying matters,” the motion from Cannizzaro's office said.

Prosecutors also pulled out a trump card in their motion to dismiss the lawsuit: the legal concept of prosecutorial immunity. American law has long held that prosecutors have “absolute immunity” from liability for what they do in the courtroom.

The phrase “absolute immunity,” or some variation on it, appears 54 times in the DA’s motion to dismiss the lawsuit.

“It’s exactly what it says. It’s absolute,” said Margaret Johns, a law professor at the University of California, Davis. “So if a prosecutor, on purpose, deliberately and maliciously violates someone’s constitutional rights, they’re immune.”

Johns said that if absolute immunity applies in this case, the plaintiffs could not win money damages, but they could get an injunction from the judge telling the DA's Office to stop its aggressive practices.

However, Johns said that prosecutors don’t have full immunity for actions they take before a trial. If they are acting as investigators, prosecutors enjoy a lesser, “qualified” immunity.

“The timing is really critical here,” she said. “Were these fake subpoenas and material witness warrants all coming on the eve of trial, when the DA’s trying to get (people) to trial, or (was the office) investigating to establish the case?”

If prosecutors had only qualified immunity, they would be subject to liability if they failed to follow clearly established law.

It could take months or longer before the judge rules on the questions of prosecutorial immunity.

Meanwhile, the plaintiffs’ lawyers ramped up their allegations in an amended version of the lawsuit filed in January. Among other things, the groups pointed to a pair of documents newly obtained under a public records request.

First Assistant District Attorney Graymond Martin, who is Cannizzaro’s top lieutenant, told The New Orleans Advocate in April that he had discouraged prosecutors from using documents marked “subpoena” unless they had a court order.

“I would not recommend it, and have recommended that it not be used,” Martin said.

Yet a May 2014 email from Martin’s secretary told a different story. She sent dozens of prosecutors a template for a bogus subpoena and told them to save it on their computers, “as per the First Assistant D.A. Graymond Martin.”

The plaintiffs cite that email as proof that the office's top brass “directly instructed prosecutors to engage in unconstitutional practices.”

The plaintiffs also cited another internal document, a jocular training slide show from Chief of Trials David Pipes, as evidence of what they call a “win at all costs” mentality.

In the slide show, which appears to have been intended for internal consumption only, Pipes instructed trial attorneys on how to handle witnesses who suddenly recant, including “family,” “addicts” and “snitches.”

The training also addressed how prosecutors could obtain material witness warrants.

“Your witness will not show up,” one slide said. “Your witness will change his mind. Your witness will not remember. Your witness will lie. Now … what are you going to do about it?”

Follow Matt Sledge on Twitter, @mgsledge.