With the gun debate intensifying in the wake of last weekend’s mass shootings in El Paso and Dayton, Ohio, the National Rifle Association’s problems deepened Monday evening as the New York attorney general’s office issued a subpoena seeking documents from more than 90 current and former members of the organization’s board.

[New York Attorney General Letitia James sues the NRA.]

The subpoena is an escalation of a continuing investigation into the tax-exempt status of the N.R.A., which is chartered in New York, and engulfs the organization’s board of directors in the inquiry. The subpoena seeks financial records and other documents that would shed light on spending decisions made by the board.

The latest moves come in a year when the N.R.A. and its board have been in turmoil. Its finances and political machine are being strained amid a host of legal battles, as well as a rebellion from some donors and members and infighting that has led to the departures of the board’s president, Oliver North, and the N.R.A.’s top lobbyist and second-in-command, Christopher W. Cox.

A spokeswoman for Letitia James, the New York attorney general, who opened the inquiry in April, declined to comment. Ms. James’s office has broad authority to investigate nonprofits, and has been scrutinizing whether the N.R.A. was using funds designated for charitable purposes appropriately, and if payments made to board members, officers and affiliated parties complied with relevant tax laws and fiduciary requirements.