Frederick Chilton is a psychiatrist and Warden at the Baltimore State Hospital for the Criminally Insane. he was a friend of Hannibal Lecter, a rival and antagonist to Dr Alana Bloom and assisted Jack Crawford in Will Graham's case. He was Will's therapist and believed that he was responsible for the copycat killings until he started to suspect Hannibal Lecter. Hannibal in turn framed Chilton for the copycat murders and for being the Chesapeake Ripper, sealing the case against him with the testimony of the mentally-damaged Miriam Lass, whom the Ripper held captive for years and whom Jack Crawford trusts implicitly. Miriam then shoots Chilton in an attempt to kill him and he is presumed deceased.
We know however the Chilton is not dead as he is still at the Baltimore State Hospital for the Criminally Insane in the film Silence of the Lambs.
He also coins the name Hannibal the Cannibal, the same name that Clarice Starling uses when Crawford asks her to interview Hannibal in Silence of the Lambs