The circular firing squad at the National Rifle Association claimed another victim on Thursday, as the gun rights group suspended its chief lobbyist for his alleged involvement in a failed coup attempt against NRA CEO Wayne LaPierre.

As the New York Times reported, the accusation against Chris Cox was made in a lawsuit the NRA filed Wednesday in New York State Supreme Court against the NRA’s erstwhile president Oliver North.

This is a bombshell development given that Cox was one of the most visible faces of the NRA. He has worked for the NRA since 1995, serving as executive director for the Institute for Legislative Action — the NRA’s lobbying arm — since 2002. He was just reelected to his position at the board meeting this April.

Cox spearheaded lobbying for the group, and garnered respect within the organization. His branch – the ILA – is seen as one of the NRA’s most effective components, blocking any meaningful gun control legislation from going through Congress mass shooting after mass shooting.

It’s the latest development in the escalating battle between North and LaPierre, which began when the NRA sued its longtime ad firm, Ackerman McQueen, for refusing to disclose details of North’s lucrative separate contract with the Oklahoma City-based firm. North has accused LaPierre and other NRA bigwigs of wasting the company’s dwindling funds on frivolous expenses, and launched a failed coup attempt against LaPierre ahead of the board meeting in Indianapolis.

Per the NRA’s lawsuit, Cox exchanged emails and texts that showed he was in on the whole thing.

The lawsuit was brought by William Brewer III, the NRA’s longtime legal counsel and the son-in-law of the head of Ackerman McQueen. A leak of documents in May showed North accusing Brewer of draining cash from the gun group at “mindboggling speed,” allegedly billing it $18.5 million for 13 months of work.

NRA spokesman Andrew Arulanandam told the Times that Cox had “been placed on administrative leave” and that an internal review was underway.

Cox’s departure suggests that a deep rift between the NRA and the ILA – its lobbying arm – may be beginning to emerge.

The Times quoted an NRA-ILA spokeswoman as saying that Cox and LaPierre “worked closely together for a quarter of a century, and any notion that Chris participated in a coup is absurd. Chris Cox is known as a calming force who always acts in the best interests of our members by effectively defending the Second Amendment, so it’s not surprising that board members would reach out to him for advice during tumultuous times.”

Cox, in a statement to the Times, called the allegations “offensive and patently false.”

“For over 24 years I have been a loyal and effective leader in this organization,” he said. “My efforts have always been focused on serving the members of the National Rifle Association, and I will continue to focus all of my energy on carrying out our core mission of defending the Second Amendment.”

The lawsuit names another NRA board member – former Rep. Dan Boren (D-OK) – as participating in the alleged coup.

An exhibit attached to the New York state complaint purports to show Boren, head of another Ackerman client called Chickasaw Nation, telling another Chickasaw employee that he was worried that Ackerman was charging the NRA for “full salary to these employees that may have been working on our accounts.”

“I bet Ackerman is in trouble on this one,” he added.