Unschuldsengel (1994)

Christoph Hansen, 16 year old son of a well-to-do Hamburg family is shocked when is father is arrested as a suspect in the murder of a male teen prostitute. Resolved to find the real killer on his own to clear his family name, he starts his investigation in the seedy part of town around the central station, where the street kids hang out - only to find that there's a whole different world that normal people like him don't usually see.