The Central Intelligence Agency (CIA) spied on famed activist and linguist Noam Chomsky in the 1970s, documents obtained by Foreign Policy confirm. While the CIA long denied it kept a file on Chomsky, a Freedom of Information Act (FOIA) request filed by an attorney and given to reporter John Hudson has confirmed that the CIA snooped on the professor from MIT.

Furthermore, the CIA appears to have scrubbed its record on Chomsky–a potential violation of the law.

For many years, similar requests for Chomsky’s CIA file were met with responses denying that the record existed. But FOIA attorney Kel McClanahan sent a request to the Federal Bureau of Investigation, and it garnered a document showing FBI and CIA communication about Chomsky.

The 1970 document is about Chomsky’s anti-war activities and asks the FBI to gather more information about a trip to North Vietnam by anti-war activists. The memo notes that Chomsky endorsed the trip. “The June 1970 CIA communication confirms that the CIA created a file on Chomsky," Athan Theoharis, an expert on FBI-CIA cooperation, told Foreign Policy. “That file, at a minimum, contained a copy of their communication to the FBI and the report on Chomsky that the FBI prepared in response to this request.”

Theoharis added that it was clear the CIA “tampered” with the file. “The CIA's response to the FOIA requests that it has no file on Chomsky confirms that its Chomsky file was destroyed at an unknown time,” he said, referring to the fact that past FOIA requests to the CIA were met with responses that no file on Chomsky existed.

Destroying records could run afoul of a 1950 law that requires government agencies to obtain advance approval before from the national archives before destroying records.

Theoharis also said the possible destruction of Chomsky’s file means that other files compiled by the CIA were also likely destroyed. A more recent precedent for that type of behavior was the 2005 destruction of CIA tapes showing high-level terrorism suspects being waterboarded.

In response to the revelation, Chomsky told Foreign Policy: “Some day it will be realized that systems of power typically try to extend their power in any way they can think of.”