1. Lewis Powell
Lewis Powell conspired with John Wilkes Booth to assassinate Abraham Lincoln.
Powell had been a Confederate war prisoner. Tall and sturdy, he was hired to deliver the muscles of a kidnapping plot. When that plot failed, Booth commissioned Powell to assassinate Secretary of State William Seward. He entered the Seward home and seriously injured Seward, Seward's son, and a security guard.
Powell tried and was convicted, and was executed by hanging in July 1865.