The Republican Washington state representative Matthew Shea “participated in an act of domestic terrorism against the United States” and represents a threat of political violence, according to a report produced for the Washington state legislature.

Shea is a far-right figure who holds extremist Christian, nationalist and Islamophobic beliefs. The report said it had made the judgment over terrorism by his actions before and during an armed takeover and standoff at the Malheur national wildlife refuge in 2016 in Oregon.

The report further contends that in a document entitled the Biblical Basis for War, Shea “advocated the replacement of US democracy with a theocracy and the killing of all males who do not agree”.

In its conclusion, while commenting that Shea is not an “imminent direct threat … it is more probable than not that Representative Shea is likely to plan, direct and engage in additional future conflicts that could carry with them significant risk of bloodshed and loss of life”.

It adds: “Representative Shea presents a present and growing threat of risk to others through political violence.”

In response to the report, the Washington Republican state legislative minority leader, JT Wilcox, announced on Twitter that Shea had been suspended from the house Republican caucus.

The report was commissioned by the house and produced by an outside agency, the Rampart Group, following reporting from the Guardian and other local and national outlets on Shea’s activities.

It says Shea “planned the 2016 takeover of the Malheur National Wildlife Refuge; engaged in the conflict by directing Cows (Coalition of Western States) members and militias in support of the takeover; and traveled to Burns, Oregon, and met with refuge armed occupiers contrary to appeals and warnings from law enforcement and Oregon state elected officials”.

The occupation of the wildlife refuge near Burns lasted 41 days in January and February 2016. During that time one of the occupiers, LaVoy Finicum, was shot dead at a roadblock by Oregon state police.

The report says that Shea “participated in a total of four meetings with [occupation leader] Ammon Bundy that took place within three to five days in advance of the armed takeover”, meetings which were corroborated by three witnesses.

The report implicates other Republican politicians from western states in Shea’s activities during the occupation.

On the first day of the occupation, Shea circulated a “military style operations plan”, codenamed “Operation Cold Reality”, via encrypted email to Cows members. They included the Idaho state representative Heather Scott, the Nevada assemblywoman Michele Fiore, Shea associates Anthony Bosworth and Jack Robertson, and Anne Byrd, whose husband, Barry, is the pastor for the secretive, patriot movement-aligned Marble community church in Stevens county, Washington.

Shea’s instructions to members of the network included directions to “conduct reconnaissance … collect intelligence on law enforcement and government operations … establish counterintelligence and counter-recon teams”. A major target was the federal Bureau of Land Management (BLM). Shea set out the goal of “putting pressure on federal, state and local officials to address BLM tyranny”, the report said.

He continued to communicate with this network via email throughout the occupation.

Bosworth later directly participated in the occupation of the federal facility under Shea’s instructions, where he “likely committed criminal acts” including the theft of surveillance cameras.

The report further details Shea’s extensive participation in other militant patriot movement activities, including two more confrontations with the federal government – at Bunkerville, Nevada, and Priest River, Idaho.

At Bunkerville in 2014, when the Bundy family and their supporters staged an armed confrontation with federal authorities over unpaid grazing fees, the report says Shea first despatched Bosworth to the area, issued a call to arms so that others in the patriot movement would make the journey, and eventually traveled there himself .

At this time he also formed the Coalition of Western States, a group of patriot movement-friendly legislators and activists.

Throughout the Bunkerville incident, says the report, his actions revealed “evidence of his planning and promoting political violence against employees of the US government and law enforcement officers who were lawfully attempting to execute a federal court order”.

The report accuses Shea of participating in or condoning intimidation of political opponents, government officials, and minorities. The evidence for this includes chats between Shea and his associates first reported in the Guardian.

It also alleges that Shea engaged in counter-surveillance of law enforcement agencies. At one point Shea emailed a “detailed extensive law enforcement confidential information laying out the command and control structure of Washington state law enforcement agencies”, including “rosters of local FBI joint terrorism taskforce (JTTF) agents, Swat team member lists complete with names and badge numbers and the joint harbor operations command (JHOC) building schematics”.

Shea also engaged in militia training for “armed conflicts against federal, state and local governments”. He supported “the training of youth and young adults to fight a holy war”, as previously reported in the Guardian.

In a statement, Lindsay Schubiner from the progressive Western States Center urged the House to go even further, writing: “Shea has repeatedly demonstrated that he is unfit for public office, but today’s explosive revelations seal the deal. The Washington House of Representatives must act immediately to hold him accountable. Shea’s egregious and threatening behavior warrant removal from office.”

Shea, who rarely talks to reporters, did not immediately respond to a request for comment. In a statement issued through his lawyer to Northwest News Network, Shea wrote: “I will not back down. I will continue to fight for our shared values which have made this country such a blessing to the rest of the world.”

In a telephone conversation, Jay Pounder, the source of many of the documents which have formed the basis of the Guardian’s reporting and the investigation, said: “I’m glad that the truth has come to light. I hope the legislature does not give this a pass.”