Law Abiding Citizen

What happens to a town when a man with a gun refuses to stop another man with a gun from killing people, just because it was against the law to bring the gun on school property?

Sheldon Knapp was caught in a photograph calling 9-11 with a gun in his hand, while a vicious gunman enters the school behind him. Initially regarded as a hero, the accolades turn into contempt, as people begin saying that he could have, and should have, done more.

Sheldon Knapp's defense: He is a law abiding citizen.