Charles J Guiteau pursued various careers from the lawer to evangelist, and failed at all of them. Thinking himself an author, he published a volume of theology, The Truth, which was almost entirely plagiarised. He also wrote an unsolicited, barely coherent campaign speech for Republican Presidential candidate James Garfiled, which he felt was responsible for Garfield's election. He expected to be made Ambassador to France as a reward for his speech. After being repeatedly ignored by the President, Vice President, and various high-ranking officials, Guiteau bought a British "Bull Dog" silver handled .44 cal revolver (specifically chosen because he knew it would be on display in a museum after the assassination). On July 2, 1881, he shot Garfield twice in the back, as the President boarded a train at the Baltimore & Potomac railroad station in Washington, DC. On the morning of his execution, he composed a poem, I Am Going to the Lordy, which he recited to the crowd from the gallows immediately before he was hanged.
For further infromation on Charles Guiteau, check out The Charles J. Guiteau Collection at Georgetown For an account of his trial and execution, see The History House