An armed bystander shot a man who opened fire at a Florida park filled with over 100 people -- including children -- for a Saturday back-to-school cookout, officials said. The Titusville Police Department said in a news release the man was involved in a fistfight with another person at the Issac Campbell Park and left around 5:20 p.m. -- only to return with a gun minutes later and start shooting. A bystander, who was lawfully licensed to carry a firearm, then shot the gunman.