During the Battle of Kirksville on August 6, 1862, the Union Army captured several Confederate prisoners. These were interrogated by Union Colonel John McNeil or some of his men who learned that 17 of the 47 captives had been paroled. This meant they had previously served in the Confederate Army and had been taken prisoner a first time by Union forces. They were paroled if they would swear an oath not to take up arms against the United States again. Since they had violated this oath by again serving as a Confederate soldier, they could be executed by firing squad.