Anti-war activists in Philadelphia who broke into an FBI office and stole thousands of documents in 1971 are revealing their identities and talking publicly for the first time about their bold protest.

The burglars were never caught, and the documents they sent anonymously to reporters kicked off a series of revelations about the extensive spying carried out by the Federal Bureau of Investigation (FBI) on protest groups.

They spoke with media Tuesday in honor of the release of Betty Medsger's book about them, "The Burglary: The Discovery of J. Edgar Hoover's Secret FBI."

Medsger, a former reporter for The Washington Post, spent years poring over the FBI’s voluminous case file on the episode and finally persuaded five of the eight people who participated in the break-in to go public, The New York Times reported.

“When you talked to people outside the movement about what the FBI was doing, nobody wanted to believe it,” one of the burglars, Keith Forsyth, told the newspaper, finally revealing his involvement. “There was only one way to convince people that it was true, and that was to get it in their handwriting.”

The group cased the FBI office in the suburban town of Media, Penn. for months before picking a lock to get in on March 8, 1971. They filled suitcases full of government files that showed the agency targeting protesters, and they shared the documents with newspapers.

A lawyer says the group — which included college professors, a day-care director and a cab driver — don't risk prosecution now because of the statute of limitations.

Keith Forsyth, a 20-year-old cab driver at the time of the break-in, said they also kept quiet until now to avoid prosecution, but also because they wanted the public to pay attention to the revelations from the files.

"We wanted the focus to be on the documents we found and not on us," he said during a conference call Tuesday with reporters.