On the ice, referees may impose penalties for prohibited activities. Off the ice, the National Hockey League (NHL) sometimes fines, suspends or expels players. The criminal justice system has also been known to investigate, charge and convict players. As a result, hockey has become much more regulated and the violent element much more controlled. This has been aided, in no small part, by dramatic increases in disciplinary processes and technology allowing for a high level of scrutiny of any event which occurs.