North Rhine-WestphaliaTranslated is the state, where Cologne is. Translated from NRW:
“The Interior Ministry in North Rhine-Westphalia announced that it this state alone the police has carried out 78,000 operations in refugee centers in 2015.
Nearly 90 percent of the cases had preventive character, in ten percent of the operations the police responded “due to a specific event”, such as crime or requests for assistance.
Most acts occurred mainly among refugees, says the confidential management report of the State Office for Police Services in NRW. The offenses are mainly to theft and assault.”
To get an impression of the violence and chaos when police and ambulances enter riots in a refugee camp, here is a video from Holland: