On 1 June 1941, Posse hired Reimer, with whom he had worked since 1939, as his assistant for the _Sonderauftrag Linz. On 20 October 1941, Reimer gained full authority to act as Posse’s deputy. After Posse’s death in December 1942, Martin Bormann authorized _Reimer on 25 January 1943 to act as the _Sonderauftrag’s _interim director until Voss’ appointment on 15 March 1943. In his position, Reimer was responsible for selecting, purchasing, and recording works of art.

On 16 June 1943, Göpel informed Reimer personally about the Schloss Collection and the ongoing negotiations between Schleier and President Laval and urged Reimer to make monies available to the account of the _Sonderauftrag Linz _for the eventual purchase of the collection. Throughout the acquisition of the Schloss Collection, Göpel and Reimer kept each other informed.

Since 1944, Reimer directed the evacuation and storage of art treasures in the Altaussee salt mine.

After the war, Reimer continued his work as an art expert and monument conservator and successfully concealed his involvement with the Sonderauftrag Linz, even during his arrest by the Soviet Military Administration. By the 1980s, attention focused on Reimer’s involvement once again when the German Democratic Republic’s Ministry of State Security started investigating the whereabouts of the Amber Room.

Sources:

M1782-OSS Art Looting Investigation Unit Reports, 1945-46. Consolidated Interrogation Reports (CIR). Report Nr. 4: Linz: Hitler's Museum And Library. https://www.fold3.com/image/232002470. Accessed 14 June 2021.

Muller-Kelwing, Karin and Gilbert Lupfer. _Zwischen Kunst, Wissenschaft Und Politik: Die Staatlichen Sammlungen Fur Kunst Und Wissenschaft in Dresden Und Ihre Mitarbeiter Im Nationalsozialismus. _Cologne: Böhlau, 2020.

Schwarz, Birgit. Hitlers Museum. Die Fotoalben Gemäldegalerie Linz: Dokumente zum "Führermuseum". Wien: Böhlau, 2004.

Iselt, Kathrin. _"Sonderbeauftragter des Führers" der Kunsthistoriker und Museumsmann Hermann Voss (1884-1969). _Cologne: Böhlau, 2010.