With a county office, not the police. It doesn't matter too much since most people are somewhere "in the system" anyway: pretty much everyone is registered wit

With a county office, not the police. It doesn't matter too much since most people are somewhere "in the system" anyway: pretty much everyone is registered with various social security systems, employed people are known through income tax handling, etc. (We also have rather strict rules on name changes and other means that could allow someone to make themselves disappear)