From the Document: "The Director of the Federal Bureau of Investigation (FBI) is appointed by the President by and with the advice and consent of the Senate. The statutory basis for the present nomination and confirmation process was developed in 1968 and 1976, and has been used since the death of J. Edgar Hoover in 1972. From 1973 through 2017, eight nominations for FBI Director were confirmed, and two other nominations were withdrawn by the President before confirmation. The position of FBI Director has a fixed 10-year term, and the officeholder cannot be reappointed, unless Congress acts to allow a second appointment of the incumbent. There are no statutory conditions on the President's authority to remove the FBI Director. From 1973 through 2017, two Directors were removed by the President. President William J. Clinton removed William S. Sessions from office on July 19, 1993, and President Donald J. Trump removed James B. Comey from office on May 9, 2017."
CRS Report for Congress, R44842