A Pennsylvania man's guilty plea and prison sentence for attacking police during the U.S. Capitol riot has remained under seal for months, but a court filing on Monday reveals a reason for the unusual secrecy: He cooperated with federal authorities after the Jan, 2021, siege.

Prosecutors want to keep certain details of Samuel Lazar's cooperation under wraps, but they have acknowledged for the first time that he supplied the government with information as part of a plea agreement.

Publicly releasing information that Lazar provided could interfere with ongoing investigations, according to a joint court filing by prosecutors and Lazar's attorney. The filing, which is dated Friday but was docketed on Monday, also says Lazar “named individuals responsible for criminal conduct who may not have been charged.”

More than 1,100 people have been charged with Jan. 6-related crimes, and hundreds of them have pleaded guilty. But it is rare for records of a guilty plea and sentence to be sealed, even in cases involving a defendant's cooperation. Court hearings and records are supposed to be open and available to the public unless there’s a compelling need for secrecy.

Lazar, 37, of Ephrata, Pennsylvania, was released from federal custody on Sept. 13 after serving a 30-month prison sentence. His cooperation with the government was discussed at a March 2023 sentencing hearing that was closed to the public, the joint filing says.

A coalition of news outlets, including The Associated Press, on Friday renewed its request for the court to unseal records of Lazar's guilty plea and punishment. Prosecutors and Lazar's attorney are asking for 30 days to redact records of his cooperation before they are publicly released.

U.S. District Judge Amy Berman Jackson, who sentenced Lazar, didn't immediately rule on either request.

In May, Jackson had rejected the initial request from media outlets to release any sealed records that may exist. Jackson said the case law cited by the press coalition “plainly recognizes that there may be circumstances where a need for secrecy can be outweighed by competing significant interests.”

Lazar was arrested in July 2021 on charges that he came to the Capitol on Jan. 6 dressed in tactical gear and protective goggles and used chemical spray on officers who were trying to hold off the mob of Donald Trump supporters.

Videos captured Lazar approaching police lines outside the Capitol and discharging an orange chemical irritant toward officers, an FBI agent said in a court filing. Lazar shouted profane insults at police through the bullhorn, calling them tyrants and yelling, “Let’s get their guns!”

Lazar remained jailed for nearly two years before his sentencing. A magistrate judge who ordered Lazar's detention concluded that his pretrial release would pose "a concrete, prospective threat to public safety.”

Attorneys for the news outlets questioned why records of Lazar's guilty plea and sentence remained under seal even after his release from prison.

“The press, the public, and presumably even the police victims of Lazar’s violence on January 6 therefore have no idea how or why this January 6 riot participant, deemed just a couple of years ago to be too dangerous to release, is now free,” the lawyers wrote on Friday.

As recently as last month, the Justice Department refused to say why the case remains under wraps, while attorneys for Lazar did not respond to multiple requests for comment from The AP.