Timeline: A troubled history of FBI appointments, dismissals

James Comey, Director of the Federal Bureau of Investigation (FBI) was dismissed by President Donald Trump on Wednesday. The unusual move was only the second time when the director was removed untimely in the history of FBI.

Here is a list of troubled appointments and dismissals in the history of the FBI:

James Brien "Jim" Comey Jr. - September 4, 2013: Nominated by former President Barack Obama, Comey replaced outgoing director Robert Mueller. He was dismissed by President Trump on grounds of conflict in investigation of Hilary Clinton's emails.

William Steele Sessions- November 2, 1987: Sessions was nominated to succeed William H. Webster as the 4th FBI Director by President Ronald Reagan. He was removed by Bill Clinton on July 19 1993, after Department's Office of Professional Responsibility (OPR) accused him of numerous ethical lapses.

Louis Joseph Freeh- September 1, 1993: Freeh was sworn in as 5thdirector of FBI replacing acting director Floyd I. Clarke. His appointment occurred while FBI was involved in a number of high-profile incidents and internal investigations. He resigned on June 25, 2001 amid criticism FBI needed stronger leadership.

Louis Patrick "Pat" Gray III- May 3, 1972: Gray served as acting FBI director for one year until he was forced to step down in April 1973 due to the Watergate scandal. He maintained that he was dismissed as he refused to cooperate with the White House.

John Edgar Hoover- March 23, 1935: - Hoover acted as the 1st director of FBI and 6th Director of the Bureau of Investigation. He remained the director of FBI till his death in May 2, 1972. The controversial legacy left by Hoover as a director where critics accused him to abuse his powers, FBI directors subsequently were limited to 10 year term, extended only by the U.S. Senate.