The National Rifle Association’s annual convention was consumed by infighting on Saturday, after its president, Oliver North, was ousted by its board and its longtime chief executive, Wayne LaPierre, a week after a joint investigation by The New Yorker and The Trace exposed hundreds of millions of dollars in questionable payments to N.R.A. executives, contractors, and venders. Adding to the scrutiny of the gun-rights group, the Times reported on Saturday that the New York attorney general, Letitia James, has opened a formal investigation into the group’s financial practices, including whether it should retain its nonprofit status.

The convention began with Richard Childress, the N.R.A.’s first vice-president, reading aloud a letter from North, whose role in the organization is largely ceremonial, to hundreds of members gathered at the Indiana Convention Center, in Indianapolis. In the letter, North said that he would not seek a second term as president and had created a committee to examine the allegations of financial mismanagement by LaPierre. “If true, the NRA nonprofit status is threatened,” North’s letter said. “There is a clear crisis that needs to be dealt with immediately and responsibly so the NRA can continue to focus on protecting our Second Amendment.”

This story was published in partnership with The Trace, a nonprofit news organization covering guns in America.

North’s announcement was followed by a raucous debate among members over a resolution calling for the resignation of LaPierre, the N.R.A.’s longtime executive vice-president and public face. The resolution, put forward by a member from Pennsylvania, accused LaPierre of having “squelched and ignored” issues raised nearly twenty years ago regarding Ackerman McQueen, an advertising firm that has shaped the group’s messaging for years and was paid forty million dollars in 2017 alone. The resolution warned that the N.R.A.’s “highly suspect” financial practices could result in its complete dismantling.

The intensity of the debate over the resolution appeared to expose deep divisions among rank-and-file members and ratcheted up pressure on LaPierre, who has led the organization for nearly three decades. Members spent almost an hour arguing over whether the N.R.A.’s financial woes should be discussed in public. “The lifeblood of this organization is on the line,” Marion Hammer, an influential, Florida-based N.R.A. lobbyist and former president, said. “We are under attack from without; we do not need to be under attack from within.” Members then voted to keep the debate private and send the resolution to the board, which is scheduled to meet on Monday.

On Friday, the Wall Street Journal reported that LaPierre had told the group’s board that North was threatening to release a letter containing “a devastating account of our financial status, sexual harassment charges against a staff member, accusations of wardrobe expenses and excessive staff travel expenses.” In a move that surprised many members, the N.R.A. sued Ackerman McQueen earlier this month, accusing the firm of concealing financial information.

North’s ouster added an element of intrigue to what is normally a weekend of firearm-themed festivities. When the convention kicked off, on Friday morning, attendees browsed acres of guns and accessories across the exhibition floor. Later, they ventured across the street to the Lucas Oil Stadium, where conservative politicians and celebrities, including President Trump, delivered a series of speeches. Trump drew cheers when he announced that the U.S. was withdrawing from the landmark U.N. Arms Trade Treaty, an agreement signed by Barack Obama in 2013 that aims to regulate the sale of weapons. Chris Cox, the N.R.A.’s top lobbyist, had derisively labelled the agreement the “United Nations Arms Ban Treaty.”

When members assembled in the convention center’s second-floor ballroom to hear from their leaders on Saturday morning, tensions were visible. LaPierre walked onstage to a standing ovation and took a seat at the table with his fellow-executives. North’s decision to skip the meeting, though, left the chair next to LaPierre empty. LaPierre remained staid as Childress read North’s letter. LaPierre later walked up to the lectern and hewed to familiar talking points, ignoring North’s resignation. Wearing a blue suit and tie, LaPierre touted the N.R.A.’s success in rolling back gun restrictions and resisting efforts by state officials, including the governor and attorney general of New York, to enact gun-control measures. “We are in the fight for our political lives here at the National Rifle Association,” LaPierre said, as the crowd applauded. “But I promise you, in the spirit of true patriots, we are fighting back.”

The subsequent debate over LaPierre was impassioned, with members who opposed him shouting from the back of the room, “We demand to be heard.” When the N.R.A.’s secretary and general counsel moved to send the resolution calling for LaPierre’s ouster to the board so that it could be discussed in private, citing ongoing litigation and an internal review, it elicited boos from the crowd. “If this is indeed an issue that should not be discussed in front of the media, perhaps we should ask the media to leave the room,” Adam Kraut, a gun-rights advocate who has become vocally critical of LaPierre, told the board. “Because, last I looked, the sign outside said this was a meeting of the members.” After roughly forty-five minutes of debate, the members passed the resolution referring the issue to the board.

Throughout the convention, N.R.A. members said they remain deeply suspicious of the news media and see investigations by Democratic officials in New York State as biased. Beth Dragoo, who has belonged to the N.R.A. for more than forty years, said, “I tend to want to dig into the facts for myself, and find out through the organization what’s going on rather than trying to think that someone who doesn’t belong to the organization could possibly know more.”