James W. McCord Jr., a security expert who led a band of burglars into the shambles of the Watergate scandal and was the first to expose the White House crimes and cover-ups that precipitated the downfall of the Nixon administration in 1974, died on June 15, 2017, at his home in Douglassville, Pa. He was 93.

The death went unreported by local and national news organizations at the time. It was apparently first reported by the London-based writer and filmmaker Shane O’Sullivan in his book “Dirty Tricks: Nixon, Watergate, and the CIA,” published last year. The news of the death surfaced again on March 31 on the website Kennedys and King.

The United States Department of Veteran Affairs confirmed his death on its online Nationwide Gravesite Locator. (Mr. McCord was buried in Indiantown Gap National Cemetery in Annville, Pa.) The Washington Post said the cause was pancreatic cancer, quoting Mr. McCord’s death certificate, which the newspaper said it had obtained from the Berks County Register of Wills office in Reading, Pa.

In the large cast of liars, schemers, money launderers, character assassins and other scoundrels who devised “dirty tricks” to damage President Richard M. Nixon’s political opponents, it was Mr. McCord, a retired spy with a shadowy past, who broke the silence of a shaky Oval Office conspiracy. It had been held together with hush money, fears of prison and, if all else failed, promises of presidential clemency.