The Order Police battalions were militarised formations of the German Order Police (uniformed police) during the Nazi era. During World War II, they were subordinated to the SS and deployed in German-occupied areas, specifically the Army Group Rear Areas and territories under German civilian administration. Alongside detachments from the Einsatzgruppen and the Waffen-SS, these units perpetrated mass murder of the Jewish population and were responsible for large-scale crimes against humanity targeting civilian populations. Order Police battalions - Wikipedia SS and Police Hitler's Police Battalions
There is a famous book on one such battalion: Daniel Jonah Goldhagen (1996), 'Hitler’s Willing Executioners: Ordinary Germans and the Holocaust' and Reserve Police Battalion 101 - Wikipedia Refreshing my memory I found this a useful counter to Goldhagen's book: Reserve Police Battalion 101 which refers to Christopher R. Browning (1993), 'Ordinary Men: Reserve Police Battalion 101 and the Final Solution in Poland'. There is a mass of academic articles on the theme and in a quick look this is from 2018: Bloomsbury Collections - Holocaust Perpetrators of the German Police Battalions - The Mass Murder of Jewish Civilians, 1940–1942 I have not read either of the books, too grim a subject after reading a tome many years ago, the title and author being lost. One of the two times I had stop reading a book; the one recalled was Alistair Horne on Verdun.
So sad that German uniformed police, sworn to protect life and property became SS members. One wonders if after the war they went back to their civvie police duties or went on trial for war crimes. There may be research on that?
Here are two Twitter threads on the OrPo by the historian and researcher Philip W Blood (whose book 'Hitler's Bandit Hunters' is highly recommended): OrPo & Daluege: https://twitter.com/BloodPhilip/status/1347962445286010881?s=20 OrPo armoured units: https://twitter.com/BloodPhilip/status/1359632569877291010?s=20
There is a short, curious Twitter thread on the "return to normality". See: https://twitter.com/J_O_Holliday/status/1360277305034235905 With this opening photo below, in Leipzig September 1945.