Robert Ritter (1901–1951), right, during registration work, around 1940, Germany. Ritter headed the Racial Hygiene Research Unit (RHF) in Berlin. With its comprehensive data collection, publications and policy advice, the RHF provided the practical and ideological basis for the systematic and racist persecution of people stigmatised as Zigeuner, which led to the genocide. In the centre is a policeman, probably holding a riding crop in his right hand. The name of the targeted woman is not known.
The questioning of Sinti and Roma had the character of interrogations, as they took place under pressure, threats of imprisonment in concentration camps and also physical violence. After 1945, a court in the Federal Republic of Germany categorised the registration activities of the RHF as a National Socialist measure of violence.
