From Wikipedia

J. Edgar Hoover

John Edgar Hoover
(January 1, 1895 – May 2, 1972)

was the first Director of the Federal Bureau of Investigation (FBI) of the United States. Appointed director of the Bureau of Investigation — predecessor to the FBI — in 1924, he was instrumental in founding the FBI in 1935, where he remained director until his death in 1972. Hoover is credited with building the FBI into a large and efficient crime-fighting agency, and with instituting a number of modern innovations to police technology, such as a centralized fingerprint file and forensic laboratories.

Late in life and after his death, Hoover became an increasingly controversial figure. Some critics asserted that he exceeded the jurisdiction of the FBI. He used the FBI to harass political dissenters and activists, to amass secret files on political leaders,and to use illegal methods to collect evidence. It is because of Hoover's long and controversial reign that FBI directors are now limited to 10-year terms.