Alan Turing was a mathematician, logician, cryptanalyst, and computer scientist whose work on cracking the Enigma cipher in World War 2 is widely considered to have been the key to winning the war. The father of Computer Science, he conceived of the Turing Machine and the Turing Test, a standard for a machine to be called 'intelligent'. Widely considered to be a genius, However, in 1952 he was prosecuted for Homosexuality (then a crime), which ruined his career and life and led to his suicide by Cyanide poisoning in 1954.
More recently it has been pointed out that the Government had known about his homosexuality for years. Before his prosecution and later death, Turing had been working on Artificial Intelligence. There are theories that Turning managed to design a strong AI, capable of passing the Turing Test, and that the Government wanted him stopped. Some even say that he was murdered when he tried to make his work public.