The head of Cologne's police force is leaving his post "to restore public trust in the police" following scores of attacks on women in the city on New Year's Eve.<br />The violence outside the main railway station has sparked a debate about Germany's open door policy on migrants.<br />Victims described chaos as the men carried out dozens of sexual assaults and robberies with little apparent response from the authorities.<br />Federal authorities say they have identified 18 asylum-seekers among 31 suspects linked to crimes committed in Cologne on New Year's Eve.
