On the Dec. 6, 1973 "Nightly News," Carl Stern becomes the first reporter to expose COINTELPRO, a now-notorious FBI program that infiltrated and disrupted civil rights, anti-war and other political dissident groups.

The files stolen from an FBI office outside Philadelphia in 1971 were stunning, describing secret efforts to spy on student protestors and infiltrate civil rights groups.

But one document proved especially interesting to the NBC News correspondent who would later break the news of the FBI’s most notorious secret program of nationwide domestic surveillance. It discussed a proposal from bureau headquarters that agents send letters “anonymously” to college professors who had “shown a reluctance to take decisive action” against left-wing protestors. And it included a cryptic acronym he’d never seen before: “COINTELPRO.”

“The first question that popped in my mind was, ‘By what authority do FBI agents write anonymous letters?’” recalls Carl Stern, who covered the Justice Department for NBC News for nearly 30 years. He also wanted to know what “COINTELPRO” stood for. But when he pressed those questions with top DOJ officials, “nobody would talk to me about it.”

Stern recalled his efforts to learn more about the document—and the mysterious reference to “COINTELPRO” -- on Tuesday after the confession by three former peace activists that they had committed the unsolved burglary of the Media, Pa. office in order to document what they were convinced was “massive illegal surveillance” by J. Edgar Hoover’s FBI. The identities of the burglars are revealed in a new book, “The Burglary,” by former Washington Post reporter Betty Medsger, and were reported Tuesday on the “Today” show.

Read the NBC News report on the burglars who came forward.

In the bombshell book, "The Burglary," journalist Betty Medzger exposes the robbers behind the momentous theft from an FBI office outside Philadelphia over 40 years ago. The perpetrators have come forward in an interview with NBC News.

The burglars cracked open the door to exposing illicit FBI snooping by stealing the files and sending them to select journalists, but it was Stern who opened it all the way. Using a then-novel tool called the Freedom of Information Act to obtain documents from the government, Stern uncovered the long-running surveillance program known as COINTELPRO, a now-infamous effort at political intimidation and disruption that may have been Hoover's biggest secret.

As Stern recalled it, when his initial inquiries about COINTELPRO were rebuffed, he refused to take no for an answer and sought an explanation over lunch with L. Patrick Gray, who had become acting director of the FBI after Hoover died in 1972. He got back a terse letter in Sept. 1972. “This matter involved a highly sensitive operation,” it read. “It has now been discontinued” and any further disclosures “would definitely be harmful to the Bureau’s operations and to the national security.”

So Stern filed a lawsuit under the Freedom of Information Act. And with the help of a sympathetic judge, the late Barrington Parker, he finally got the first documents describing what COINTELPRO was, and broke the story on NBC’s “Nightly News” on Dec. 6, 1973. “Secret FBI memos made public today show the late J. Edgar Hoover ordered a nationwide campaign to disrupt the activities of the New Left,” said John Chancellor that night introducing Stern’s report. “He ordered his agents not only to expose New Left groups, but to take action against them to neutralize them.”

Those documents opened the floodgates to hundreds more over the years as Congressional investigations followed. They showed that Hoover had started COINTELPRO in 1956, first targeting the Communist Party and then expanding the program over the years to include the Socialist Workers Party, black nationalists, New Left groups and the Ku Klux Klan. Agents were directed to harass and intimidate leaders, plant false stories and write anonymous letters aimed at discrediting them. In one case, the bureau planted a false story that film star Jean Seberg, known to have financially supported the Black Panther Party, had been impregnated by one of its leaders. In another, it sent a tape to Coretta Scott King, wife of the civil rights leader Martin Luther King, Jr. containing secretly made audio recordings of her husband’s extramarital affairs.

“It was a very abusive program, it had no law enforcement purpose,” said Athan Theoharis, a leading scholar of the FBI’s history and a professor emeritus at Marquette University. “Clearly, what the bureau was doing was trying to contain organizations whose politics the FBI viewed as abhorrent.”

Stern agrees. “They made a decision about which individuals and organizations were doing things that they regarded as un-American and harmful,” he said, “and that’ s not the bureau’s job.”

Ironically, Hoover quietly terminated COINTELPRO shortly after the Media, Pa. break-in, afraid details of the program would come to light. Within a few years, prodded by the bad publicity and the findings of a Senate committee headed by the late Sen. Frank Church of Idaho, the Justice Department issued new guidelines prohibiting the bureau from engaging in any such activities and barring investigations based on First Amendment-protected political activity.

By then, a later FBI director, Clarence Kelley, would do something Hoover is not known to have ever contemplated. He formally apologized for COINTELPRO. "We are truly sorry we were responsible for instances which are now subject to such criticism," Kelley said in a 1976 speech at Westminster College in Missouri. "Some of those activities were clearly wrong and quite indefensible."

Theoharis said those changes might never have taken place if the Media burglars had not stolen the FBI’s secret files -- and Stern had not followed up on what they did.

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