During World War II, the Danish government chose to cooperate with the Nazi occupation force. Even though this applied to the Danish police as well, many were reluctant to cooperate. As a result, a large number of members of the Danish police force were deported to Nazi concentration camps in Germany. The Gestapo established the collaborationist HIPO Corps to replace them.
Nazi Germany occupied Denmark on 9 April 1940, and the Danish cabinet decided on a policy of collaboration. This applied to all civil servants, including the entire Danish police force, which began cooperation with its German counterparts.
On 12 May 1944, Dr. Werner Best demanded that the Danish police should protect 57 specific enterprises against sabotage from the Danish resistance movement, which was growing in strength. Should the Danish civil service not accept this, the Danish police force would be reduced from 10,000 to 3,000 men. The head of the Danish administration, Nils Svenningsen, was inclined to accept this demand, but the organizations of the Danish police were opposed to the idea. The German request was ultimately turned down, and this was reported to Dr. Best on 6 June 1944. This reduced the Gestapo's already limited trust in the Danish police even further.
The German army began arresting members of the Danish police in Denmark's main cities on 19 September 1944. The force numbered 10,000 men in that year. 1,960 personnel were arrested and later deported to the Neuengamme concentration camp. Policemen deported to Buchenwald were in two groups, the first group was sent on 29 September, the second was transferred on 5 October, 1944. On 16 December, following pressure from the Danish administration, 1604 men were transferred from Buchenwald to Mühlberg (Stammlager or Stalag IV-B), a camp for prisoners of war (POW)s. That meant an improvement in the situation for the Danish policemen; POWs had some kind of protection due to international conventions, while inmates in concentration camps did not.