Negligent Discharge, the Death of Clement Vallandigham, 1871.
In 1871 the attorney and former Ohio politician Clement Vallandigham was representing a man accused of murdering another man in a barfight. Vallandigham intended to prove that the man killed was not murdered by his client, but had accidentally shot himself in the scuffle. According to Vallandigham, the man had been knocked to the ground when he arose and attempted to draw a pistol on his client. While rising his pistol did not clear his vest, and the man cocked the hammer and accidentally shot himself in the chest.
To prove his theory Vallandigham spent an afternoon shooting his pistol at pieces of cloth at different distances to determine the pattern of the gunpowder residue. When he returned to his hotel room he placed the still loaded pistol next to an unloaded pistol he intended to use as a prop to demonstrate his point.
The next morning Vallandigham grabbed one of the two pistols and headed to court. Unbeknownst to him, he accidentally took the loaded pistol rather than the unloaded prop. Using the pistol he demonstrated to the court how the man had shot himself,
"Pretending he was Myers, Vallandigham took a pistol, then slowly pulled it out, cocking it as he drew it forth. When the muzzle cleared the pocket, he tried to place it in the exact position which he believed Myers’s weapon would have assumed at the moment when it was discharged. “There, that’s the way Myers held it,” Vallandigham said, “only he was getting up, not standing erect.” At that moment he pressed the trigger. There was a flash and the half-suppressed sound of a shot. “My God, I’ve shot myself!” Vallandigham exclaimed in shocked dismay as he reeled toward the wall and tried to hold himself up."
Vallandigham’s demonstration was very convincing to the jury and his client was acquitted. Unfortunately Vallandigham died the next morning.