Governments too. The defining characteristic of a state is the monopoly on the legitimate use of violence. Some more recent theories on state formation come down to the state being the biggest bandit of them all, the one that subsumes and threatens to kill all other organized sources of violence, and hence becomes the "legitimate" one simply because it has eliminated all other contenders. One of the most popular courses at my college was entitled "Murder", and the syllabus was largely devoted to this tension between how the worst crime of all, when talking about individuals, is simply how states do business.