Career
Before his election to the Danish parliament (Rigsdag) he was a dairyman and farmworker. On the 20 August, he and 106 of the arrested men in Copenhagen were deported from Vestre Prison to the Horserød camp. In December 1942, the Danish authorities handed him and his file over to the Gestapo for interrogation.
On 29 August 1943, following the German dissolution of the Danish government, German occupation forces took command of the internment camp where the Danish authorities held Martin Nielsen.
On 2 October 1943, he was deported as part of a group of 150 communists to Stutthof concentration camp, on the ship Wartheland via Swinemunde and by cattle car. On 25 January 1945, Nielsen was marched from Stutthof.
On 10 March 1945, he was liberated by the Red Army, which sent him (part of the way on foot) to Moscow, from where he was repatriated.
