The building was at first the business premises of jeweller Leopold Dahmen, and the building takes its name from his initials. In 1934, the Nazis rented the building from him and turned it into the headquarters of the secret police, the Gestapo. Surprisingly, the building survived the Allied bombing of Cologne during World War II, while 90% of the city was destroyed. After the bombings, the basements of the building, which had been used as prison cells and torture rooms for forced labourers and political enemies, were used to store wartime files and paperwork. Inscriptions made on the walls of the prison cells by inmates can still be viewed today. The building was the site of many executions, as well as deaths due to overcrowding and poor hygienic conditions.