John Wilkes Booth
On April 14, 1865, Booth went to Ford’s Theater in Washington, D.C. to pick up his mail.  There he found out that Lincoln and his wife would be seeing a play at the theater that evening. Booth knew the play well. He met with his co-conspirators, and they decided that around 10:15 that evening, they would kill President Lincoln, Vice-president Johnson, Secretary of State William Seward, and possibly General Ulysses S. Grant.