Gun rights groups are suing Massachusetts Attorney General Maura Healey for refusing to release public documents relating to their hosting of schematics for the 3D-printed Liberator handgun.

Brandon Combs of the California-based Firearms Policy Coalition and Brent Carlton of the Commonwealth Second Amendment advocacy group filed a Freedom of Information request with Healey’s office Aug. 8 for documents related to CodeIsFreeSpeech.com, where a download of Liberator schematics was available.

The website — hosted on Amazon web servers — went dark Aug. 1. The gun groups want to know if Healey’s office had communicated with Amazon prior to the website being taken down. The request also asked for public documents relating to their gun rights groups and the Liberator plans.

Healey’s office responded to the request for documents with a blanket denial, saying the office is “currently involved in litigation and one or more investigations concerning 3D-printed guns.

“The disclosure of any records related to these ongoing matters that have been and continue to be compiled by this Office would divulge our litigation, pre-litigation, and investigative strategies and reveal our sources of information such that our legal and enforcement positions would be compromised,” Healey’s office said in an Aug. 29 letter to Combs and Carlton.

Healey’s office claimed the documents were exempt from the open records law because they were connected with ongoing deliberations and investigations.

Combs and Carlton said in the lawsuit the “over broad and complete refusal to provide any and all responsive public records … is unlawful, arbitrary and capricious.”

The lawsuit asks a judge to order Healey to hand over the documents and pay their attorney fees and court costs.

Healey’s office, provided a copy of the lawsuit by the Herald, said it has not been served the court documents yet and so it would be premature to comment.

In mid-August, Healey’s office led a group of 22 states’ attorneys general demanding Secretary of State Mike Pompeo and Attorney General Jeff Sessions act to have the downloadable gun plans taken down.

The State Department and Justice Department entered into a settlement with the schematics’ author, Defense Distributed, allowing the company to post the plans online.

Healey and others said the ability to download and print a handgun amounted to a grave public safety threat.

A federal court in Washington state issued an injunction barring the Trump administration from allowing the plans to be put online while the court case is being argued.

Combs and other gun groups that set up CodeIsFreeSpeech.com posted the code July 31.

“We intend to encourage people to consider new and different aspects of our nation’s marketplace of ideas — even if some government officials disagree with our views or dislike our content — because information is code, code is free speech, and free speech is freedom,” the groups said.