The last time a sitting vice president shot somebody was more than 200 years ago, in the famous duel where Alexander Hamilton was killed by Aaron Burr.
Burr was Thomas Jefferson's vice president from 1801-05. On July 11, 1804, longtime enemies Burr and Hamilton faced each other with pistols in Weehawken, N.J. Burr fatally wounded Hamilton with a single shot.
A New York coroner's inquest "found a verdict of wilful murder by Aaron Burr, vice president of the United States." A New Jersey grand jury indicted him for murder, but he was never arrested. Burr presided over the Senate until his term ended.
The public learned of the shooting the next day. Benjamin Moore, the Episcopal bishop who had been called to Hamilton's side, published a letter in the New York Evening Post saying Hamilton died with no ill will toward Burr.
Sources: World Book Encyclopedia and "Duel: Alexander Hamilton, Aaron Burr and the Future of America," by Thomas Fleming.