By Matt Schudel

The Washington Post

Matthew Aid, a onetime intelligence analyst and researcher who drew on his “obsession” with the National Security Agency in writing a history of the secretive intelligence organization and revealed that once-public documents at the National Archives were quietly being reclassified and taken off the shelves, died Aug. 20 at his home in Washington, D.C. He was 60.

The cause was heart disease, said his brother, Jonathan Aid.

Matthew Aid began delving into military and intelligence matters in his early teens, then became a Russian-language expert in the Air Force before he was court-martialed in the 1980s for possessing classified information and impersonating an officer — an attempt to impress a woman, he said.

Close acquaintances said he worked for a time as an NSA analyst and spent at least 15 years as a researcher for global investigative organizations. Among other things, he examined records of companies involved in hostile takeovers and looked into emerging businesses in Russia.

Despite his court-martial, he was a researcher for the 9/11 Commission, investigating the origins of the terrorist attacks on the U.S. on Sept. 11, 2001.

By his own admission, however, Aid’s primary occupation was as an independent scholar who spent most of his time digging through documents at libraries and, especially, at the National Archives in College Park, Maryland.

Aid was particularly interested in the NSA, the country’s largest intelligence organization. He spent years working on a history of the agency before publishing his study, “The Secret Sentry,” in 2009.

He traced the agency’s history to its founding in 1952 and earlier, uncovering many examples where the NSA failed in its mission. It was slow to recognize the full scale of China’s involvement in the Korean War, did not detect Soviet missiles on Cuban soil in the early 1960s and missed many developments during the Vietnam War.

One of Aid’s most significant findings, which became publicly known in 2005, was an NSA cover-up of erroneous records related to the 1964 Gulf of Tonkin incident, in which U.S. officials alleged that North Vietnamese torpedo boats twice fired on U.S. Navy ships. The incident led to U.S. military engagement in Vietnam.

A report written in 2001 noted that U.S. intelligence officers falsified documents about a disputed attack, but the report was suppressed.

“To keep it classified simply because it might embarrass the agency is wrong,” Aid told the New York Times in 2005. “Rather than come clean about their mistake, they helped launch the United States into a bloody war that would last for 10 years.”

In 2006, after searching in vain for documents he had previously reviewed, Aid discovered a previously unknown effort to remove public records from National Archives. He believed various intelligence agencies, including the CIA and defense intelligence agencies, were attempting to conceal awkward or revealing episodes from public view.

“I like things neat,” Aid told The Washington Post in 2006. “And when I started getting the runaround from people at the Archives about why this stuff wasn’t available, that’s when I started getting angry. … They would not give me an explanation. Alarm bells started going off when that happened.”

Archives officials later revealed that more than 25,000 records had been removed and vowed to stop the practice. Many of the newly classified documents were decades old.

Timothy Naftali, then a University of Virginia history professor, said Aid had performed “a great service” in exposing the reclassification program.

“His work helps all of us fight against the culture of secrecy in Washington today,” Naftali said. “We don’t have enough watchdogs.”

Matthew Morris Aid was born March 11, 1958, in New York City. In 2012, Matthew Aid published “Intel Wars: The Secret History of the Fight Against Terror,” about the role of intelligence agencies in the post-9/11 world.