Washington(CNN) In the latest sign of turmoil at the National Rifle Association, three lawyers representing the gun-rights organization are out following departures from other top officials and several board members.

The group dismissed its longtime outside counsel Charles Cooper, according to a source familiar with the matter.

The source also confirmed to CNN that Michael Volkov, another outside counsel, resigned Thursday as did an in-house lawyer.

CNN has reached out to Cooper and Volkov for comment.

NRA President Carolyn Meadows said in a statement in a response to CNN's request for comment: "The NRA and Wayne LaPierre chose the difficult but principled path -- while others opted for the back alleys of greed, lies and betrayal."

The shakeup in the NRA's legal team comes as the group faces intense scrutiny of its finances, remains locked in a legal battle with its former ad agency, and deals with criticism in the wake of two mass shootings earlier this month.

Cooper's firing was first reported by the New York Times. The Times reported that the three departures were after an internal inquiry found that the lawyers were involved in an effort to undermine NRA chief Wayne LaPierre, who is facing accusations of lavish spending.

Former NRA president Oliver North had raised concerns about the amount of money the NRA was spending on outside lawyer William Brewer and his firm Brewer Attorneys & Counselors, according to documents obtained by CNN.

When North raised concerns about the NRA's spending, he was effectively ousted as the group's president.

LaPierre accused North of trying to stage a coup, which North denied, and the NRA later sued North.

In June, Christopher Cox, the NRA's No. 2 official and group's top lobbyist, resigned after NRA leadership accused him of participating in the scheme to overthrow LaPierre -- a charge Cox denied to the New York Times.

Jennifer Baker exited her role in July as the director of public affairs for the NRA lobbying arm.

Cox's former deputy, David Lehman, who had been filling the role of top lobbyist, is also planning to leave the organization. Earlier this week, two more high-profile board members resigned. Including country music singer Craig Morgan and NASCAR team owner Richard Childress, six of the NRA's 76 board members have stepped down within a month.

The NRA has been locked in a legal battle with its former longtime advertising partner Ackerman McQueen, and shut down production in June of its online streaming network, NRATV, which was operated by Ackerman.

The New York attorney general and Washington, DC, attorney general have opened investigations into the NRA and its foundation finances.