On December 10 , 1864 , Milligan , Bowles , and Horsey were found guilty on all charges and sentenced to hang on May 19 , 1865 . Humphreys was found guilty and sentenced to hard labor for the remainder of the war , but his sentence was later modified , allowing his release . Efforts were made to secure pardons for Milligan , Bowles , and Horsey , with the decision passing to President Andrew Johnson following Lincoln 's assassination . On May 16 the executions of Milligan and Bowles were postponed to June 2 , and Horsey 's sentence was commuted to life imprisonment . President Johnson approved commutation of the sentences for Milligan and Bowles to life imprisonment on May 30 , 1865 . The prisoners were transferred from Indianapolis to a federal prison at Columbus , Ohio
Lincoln 's assassination
Assassination of Abraham Lincoln
Lambdin P. Milligan