Edgar Hoover, He was the first director of the Federal Bureau of Investigation (FBI). Better known as J. Edgar Hoover, he headed the FBI for almost 50 years!
He had been instrumental in carrying out a deadly program by the FBI called COINTELPRO, which stood for counter intelligence program against groups and activists wanting to bring about a change to the United States.
The program was carried out upon the orders of President Dwight Eisenhower to initiate covert operations from 1956 and lasted until 1971.