As head of the local SA, Veller had the Kemna concentration camp set up in an empty textile factory in the Barmen district of Wuppertal. The Nazi Party's political opponents, including Veller's own opponents, were moved to the new camp from various locations in the region, where the mass of arrests following the Reichstag fire quickly began to overwhelm the capacity of jails and prisons. Prisoners were held in makeshift holding cells located wherever the SA could find space, in schools, churches, barracks, even the cellar where Veller's own offices were located in Schloss Jägerhof in the middle of Düsseldorf, where Veller had his SA staff guards torture the prisoners. At least one person was killed, his body dumped at the Bever Dam. Kemna opened in July 1933 and immediately began beating and tormenting the prisoners. Both the guards and their superiors, including Veller, drank heavily, and the worst of the beatings occurring when the guards were inebriated. Screaming emanating from the camp was clearly audible to those living and working nearby and rumors began circulating in Wuppertal about the torture of prisoners by the SA guards, which in turn led to pressure to close the camp.