Continued infighting gripped the National Rifle Association on Thursday after the gun group suspended Chris Cox, its top lobbyist and second-ranking official, for being part of an April attempt to oust CEO Wayne LaPierre.

The allegation of Cox’s involvement in a power struggle between Oliver North, the group’s former president, and LaPierre was contained in a lawsuit filed in New York State on Wednesday against North, which was first reported by The New York Times. While the suit was directed against North, it for the first time implicated Cox of being part of the conspiracy to unseat LaPierre. The suit said that Cox had sent texts and emails that demonstrated he was a party to the ouster attempt.

The organization placed Cox on administrative leave amid an internal review, an NRA spokesman told the Times on Thursday.

“The allegations against me are offensive and patently false,” Cox said in a statement. “For over 24 years I have been a loyal and effective leader in this organization. “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.”

Cox has been with the organization since 1995 and, since 2002, has served as executive director of the NRA’s influential lobbying arm. Along with LaPierre, he has been instrumental in turning the group into the political force it is today.

Infighting has roiled the NRA since an April investigation by The Trace and The New Yorker exposed how the organization’s leadership and preferred vendors, including its longtime marketing and public relations firm, Ackerman McQueen, had extracted hundreds of millions of dollars from the nonprofit’s budget.

On the eve of the NRA’s convention in April, LaPierre alleged that North had tried to pressure him to resign by threatening to release a document detailing new financial and harassment allegations. But in a twist, the NRA leader said those allegations came at the behest of Ackerman McQueen. North resigned within days.

Since April, the NRA and Ackerman have been engaged in their own tit-for-tat legal battle after the gun group sued its message-maker for deceptive billing practices and refusing to open up its books. The group sued Ackerman for a second time last month, accusing the Oklahoma-based firm of targeted leaks to the media that were part of a broader “coup” attempt.

Ackerman launched its own countersuit last month, in which it accused the NRA of trying to get out of paying the firm “a very substantial amount of money.” The firm followed up its claims against the NRA in a Wednesday court filing first reported by Bloomberg, in which Ackerman said the group owed it nearly $1.7 million. The firm, which produces NRA-TV for the organization, said it would shut down the network and stop other services unless the NRA posted a $3 million letter of credit.