The Atomic Energy Commission, or AEC, was a regulatory agency responsible for promoting and controlling the developement of nuclear science and technology. This agency was created by the United States Government in the 20th century.
In 1986, after Pavel Chekov had been apprehended aboard the U.S.S. Enterprise, this agency was contacted by the United States Navy. The agency sent a representive to the aircraft carrier. He observed the interrogation of Chekov by a FBI agent. When the interrogation proved unfruitful, both government employees conferred about what the next step should be. The AEC representative suggested that they should contact Washington, DC. Before the suggestion was carried through, Chekov escaped from the interrogation room. (Star Trek IV: The Voyage Home)