Former Mayor Ray Nagin was back in federal court in New Orleans on Thursday, this time to give a deposition in a civil lawsuit that accuses a local landfill owner of bribing Nagin and other politicians to get special treatment.

Reporters were not allowed to watch Nagin's testimony, but they were able to catch a glimpse of him as he shuffled down a fourth-floor corridor, shackled at the ankles and wearing a white polo shirt, dark jeans and high tops.

As he arrived, security officers cleared the hallway outside the courtroom where the former mayor's deposition was to take place.

Nagin's lawyer at his 2014 trial, Robert Jenkins, accompanied him for the deposition and said lawyers for both sides questioned the former mayor for a total of about five hours.

The lawsuit, filed in 2011 by trash-collection giant Waste Management, accuses the owners of the River Birch landfill of illegally influencing local politicians with bribes and other enticements.

One of the central claims in the suit is that Nagin's abrupt decision to close a landfill operated by Waste Management in 2006 — during a period after Hurricane Katrina when owning a dump was extremely lucrative — was the result of his receipt of $20,000 in political contributions from companies affiliated with River Birch. Nagin was elected to his second term as mayor that year. 

Jenkins said those payments were one major focus of the questioning Thursday, but that Nagin strongly denied there was any connection between the money he got from River Birch's owners and his decision to shut down the competing Chef Menteur landfill.

He added that the mayor was "sharp and on his game" and answered every question posed to him. 

According to Jenkins, Nagin also was asked numerous questions about Henry Mouton, a former state Wildlife and Fisheries Commission member who pleaded guilty to taking roughly $460,000 in bribes from River Birch's owners before the federal case against them fell apart in early 2013.

Nagin said he didn't know Mouton other than what he had read about him in news reports, Jenkins said. 

Jenkins said the lawyers for the two sides brought "tons of documents," adding that he suspects Nagin will have to be deposed one or two more times. He was headed back to prison Thursday afternoon, however.

Lawyers for River Birch and Waste Management did not return phone calls Thursday.

The proceeding was an unusual one: U.S. Magistrate Judge Karen Wells Roby ordered the federal Bureau of Prisons to bring the former mayor to New Orleans to be deposed after she said he declined to cooperate with lawyers for both sides in the case earlier this year when they visited the penitentiary in Texarkana, Texas, where he is being held.

At least that's how Roby described it in her order. Jenkins said Thursday that Nagin did not refuse to cooperate. Rather, he said, the warden declined to produce the mayor for the March 17 deposition because the parties to the suit failed to follow proper procedure.

Nagin, 60, who was convicted on 20 corruption-related charges in 2014, is about a quarter of the way through a 10-year prison term. 

Follow Gordon Russell on Twitter, @GordonRussell1.