He is not the only US president killed during office. There are three more...1865 - Abraham Lincoln
The assassination of the 16th United States President Abraham Lincoln took place on Good Friday, April 14, 1865, as the American Civil War was drawing to a close. More here.
1881 - James A. Garfield
The assassination of President James A. Garfield, the 20th President of the United States took place in Washington, D.C. on July 2, 1881, at the Baltimore and Potomac Railroad Station. More here.
1901 - William McKinley
The 25th President of the United States, William McKinley, was shot and fatally wounded on September 6, 1901, inside the Temple of Music on the grounds of the Pan-American Exposition in Buffalo, New York.