Common purpose (law)

Common purpose is a legal doctrine stating that all participants in a crime are responsible for its consequences, even if it wasn't the original intention. For example, if a gang of criminals agrees to rob a building by knocking out the security guard, they are all deemed guilty of murder if the knocker-out kills the guard. One of the more notorious uses of common purpose was the trial of the, a group of protesters in Apartheid-era South Africa sentenced to death when the mob they were part of murdered a local politician.