People are gathered at the Cologne, Germany, main station, in this Dec. 31, 2015, file photo. German police said Wednesday Jan. 6, 2016 that they are investigating whether a string of sexual assaults and thefts at New Year is linked to a known criminal network. The assaults in Cologne last week have prompted outrage in Germany and a fresh debate about immigration, after police said the perpetrators appeared to be of "Arab or North African origin." (Markus Boehm/dpa via AP)