Soldbuch issued to Gustav Seehaus in Berlin Spandau with a replacement unit in 1941.
Seehaus was promoted from Lt through to Captain by 1942.
The unit he served with is an interesting and not well known unit:
Sowjetische Kriegsgefangenen-Bau- und Arbeits-Bataillon 103
The Soviet prisoner of war construction and labor battalion 103 was set up on October 28, 1941 in Fürstenberg an der Oder by the Landesschützen Battalion 343 and placed under military district III (BERLIN). The battalion was deployed in the Berlin-Spandau and Berlin-Staaken area. The battalion consisted of Soviet prisoners of war and had a maximum strength of 1,900 men.
According to the book:
Kriegsgefangen in Brandenburg: Stalag III A in Luckenwalde 1939 -1945
His unit was stationed in : Kloster Zinna
The tasks performed by the units were mainly construction tasks and manual labour. Batl 103 mainly operated in the Berlin Staaken and Spandau areas as well as near Kloster Zinna.
It is highly likely Seehaus got caught up during the Battle for Berlin.