The Republican politician Matt Shea connected close allies with a group offering training to young men in “biblical warfare” that includes how to use knives, pistols and rifles, with lessons based in part on the teachings of a Georgia-based neo-Confederate pastor, emails obtained by the Guardian reveal.

Shea, who is an elected Washington state representative, later made videos in support of the group, and appeared alongside them at a gathering at a religious community in remote eastern Washington. He also paid the founder of the group money from his campaign fund in 2018.

The emails, sent in July 2016, begin with an email from Patrick Caughran, who presents himself as the founder of a training group called Team Rugged. They were provided to the Guardian by a former Shea associate who was copied in on the exchange.

Caughran asks Shea to publicize a link to the group’s Facebook page, and put him in touch with “John Jacob Schmidt”, the nom de guerre of Shea associate, Jack Robertson. Robertson is a rightwing podcast host who advocates for conservatives to move to the “American Redoubt” in eastern Washington, Idaho and Montana, and, with Shea, campaigns for eastern Washington to secede and form its own state.

On Team Rugged website, it is described as “a Christian organization that strongly believes in building manly character and the capability to stand in adversity in young men”.

In his email to Shea, however, Caughran offers a different description, saying that the group exists “to provide patriotic and biblical training on war for young men”.

He continues: “Everything about it is both politically incorrect and what would be considered shocking truth to most modern Christians.”

Caughran also wrote: “There will be scenarios where every participant will have to fight against one of the most barbaric enemies that are invading our country, Muslims terrorists (sic)”.

Caughran goes on to detail the group’s training regime, writing that “there will be biblical teaching (some taken from pastor John Weaver’s works) on biblical warfare, the responsibilities, regulations, principles and mindset. So that our young men will be better prepared to fight against physical enemies, and to do so, God’s way and with His blessing”.

The Georgia-based Weaver is a controversial preacher whom the Southern Poverty Law Center says is a “leading proponent for training Christians for armed battle”.

As well as being a preacher, Weaver is a firearms instructor, and according to the SPLC has given weapons training to members of the League of the South, a neo-Confederate group which marched at the far-right Unite the Right rally in Charlottesville in August 2017 that ended in the death of a protester.

White nationalist demonstrators walk into Lee park surrounded by counter demonstrators in Charlottesville, Virginia, 12 August 2017. Photograph: Steve Helber/AP

In his email to Shea, Caughran goes on to list weapons training as part of the event for attendees. The training will “show them how to work better as a team, both in achieving physically demanding tasks and on the battlefield. Those who attend will learn combatives, the use of a knife in defense, close quarters shooting with rifle and pistol and how to work effectively in teams of 2, 3 and 4.”

In response to the request for Facebook promotion, Shea responds, from an address associated with his law practice, “It is scheduled to post tomorrow”. He then forwards it to Robertson aka John Jacob Schmidt, writing, “See below. From Marble meeting. JJS he wants to connect with you”.

An LLC called Team Rugged was registered in Washington in 2017 under the name of Michael P Caughran, 23, a resident of Colville, Washington, the seat of Stevens county. The email address in the filing is similar to the one that Caughran used to communicate with Shea.

In filing materials the business is described as providing “OUTDOOR ACTIVITIES FOR YOUNG MEN AND BOYS TO INCREASE THEIR GOOD CHARACTER AND SKILLS TO PERFORM IN TEAMS AND LEADERSHIP ROLES”. The business filed its most recent annual report in August 2018.

An initial filing for the LLC lists the executors of the company, including Barry Byrd, the pastor of Marble Community fellowship, as well as Lucas Olson and Michael Caughran, both of Lewiston, Idaho.

Marble Community Fellowship is a Christian community led by pastor Barry Byrd , with a compound on the Columbia River, not far from the Canadian border. It believes in rule by their interpretations of biblical law.

As of late July 2019, Team Rugged’s website listed Byrd as an instructor along with Caughran. The Team Rugged Facebook page listed several events in recent years at the Marble compound, including battles with Airsoft guns. Pictures on the Team Rugged website show young boys in fatigues in the forest, armed with Airsoft guns.

In 2018, representative Shea was revealed to have distributed a document entitled “Biblical Basis for War”, which appeared to lay out a plan for a theocratic takeover, including the instruction to “kill all males”. Shea denied this interpretation of the document, saying instead that the material was notes for a sermon.

In 2015, the year before the Team Rugged email from Caughran, Weaver appeared alongside Shea at the annual God and Country celebration at Marble.

Last May, the Guardian revealed that at the 2018 God and Country event, Shea warned of civil unrest while Robertson urged the audience to prepare for civil war.

In a video posted to his Facebook page, Shea interviews Team Rugged at the 2017 God and Country event, where he described the group as “returning to basic patriot principles”.

Matt Shea walks off the house floor to attend a caucus meeting, 22 April 2019, at the capitol in Olympia, Washington. Photograph: Ted S Warren/AP

Shea, who rarely speaks to the media, and once called journalists “dirty, godless, hateful people”, did not respond to detailed questions sent via email.

Caughran did not immediately respond to a request for comment.

Longtime Shea critic, and Republican, the Spokane county sheriff, Ozzie Knezovich, said in a telephone conversation that “it almost sounds like going back to the Hitler Youth concept”.

Knezovich added: “There are lines that should never crossed. When you indoctrinate children in radicalized hate, then we wonder why we have the kind of shootings and bombings that we have around the world.”

A spokesman for the Washington Republican minority leader, JT Wilcox, did not immediately respond to a request for comment.

Since the Guardian’s previous revelations about Shea’s involvement in private chats, and his appearances on podcasts and public events, Washington’s state house has commenced an investigation into his activities, and has hired an outside firm to investigate Shea’s associations with political violence.