DURING a turbulent and contentious term in power spanning almost 50 years, J Edgar Hoover was instrumental in the fight against mounting criminality on the streets of America. In 1924, he was appointed director of the Bureau of Investigation, which became the FBI. The film opens with Hoover (Leonardo DiCaprio) clinging to power, assisted as ever by loyal secretary Helen Gandy (Naomi Watts).

He begins to dictate his memoirs to Agent Smith (Ed Westwick) and drifts back in time in hazy reminiscences to the 1919 bombings which sent shockwaves through Washington DC.

With FBI assistant director Clyde Tolson (Armie Hammer) by his side, Hoover becomes embroiled in the ill-fated search for the missing infant son of aviator Charles Lindbergh (Josh Lucas) and clashes with Robert F Kennedy (Jeffrey Donovan).