After Booth assassinated Lincoln on April 14 , 1865 , Arnold was arrested from his job in Virginia on suspicion of complicity . He admitted his part in the plot to kidnap Lincoln , and his co-workers supported his contention of being in Virginia at the time of the assassination . During the trial , one of the chief witnesses was Louis J. Weichmann , a boarder at Mary Surratt 's ( John Surratt 's mother )
assassinated Lincoln
Assassination of Abraham Lincoln
Samuel Arnold (conspirator)