On 9 April 1940, Nazi Germany launched Operation Weserübung and invaded Denmark. While the country initially experienced a relatively cooperative occupation, growing resistance and sabotage by 1943 pushed the Gestapo to rely increasingly on Danish collaborators to hunt down opponents of the regime.

One of the most feared was Ib Birkedal Hansen, a Danish Gestapo informer who led a powerful network of collaborators in Copenhagen known as the Birkedal Group. Through torture, intimidation, and a wide network of informers, Hansen and his men were responsible for an estimated 60 percent of arrests in occupied Denmark.

After the liberation in May 1945, Hansen went into hiding but was eventually captured and brought back to Copenhagen to face justice. Convicted of numerous crimes committed during the occupation, he ultimately paid for his actions.