(JTA) — After years of denial, the Central Intelligence Agency acknowledged that it kept a file on Noam Chomsky, though the file appears to have been destroyed.

Chomsky, 84, an American academic who works as a professor at the Massachusetts Institute of Technology, was an anti-war activist in the 1970s. He is a vociferous critic of Israel.

Freedom of Information Act requests to the CIA over the years had not turned up Chomsky’s file, but a request to the Federal Bureau of Investigation by Chomsky biographer Frederic Maxwell turned up a memo between the CIA and the FBI confirming the existence of a CIA file on Chomsky, according to The Cable blog in Foreign Policy.

The June 8, 1970 CIA memo outlines Chomsky’s anti-war activities and asks the FBI for more information about a trip to North Vietnam by anti-war activists. The trip, according to the memo, has the “endorsement of Noam Chomsky” and requests more information on Chomsky and the others associated with the trip.

An expert contacted by the blog said the FBI memo confirms that a Chomsky file once existed, though it was likely destroyed.