Influenced by his father, Josef Mohren founded a communist youth group at the age of 16. This led to his arrest and detention in prison. After his release, Mohren joined the Aachen Combat League against Fascism. Since the beginning of the war, him and his like-minded friends had followed the events via BBC Radio. He was fascinated by the direct reporting, which also called for withholding any support for Hitler's war machine. As a result, Josef Mohren decided to work only in the materials distribution section at the Gouley mine, in order to avoid having to work in coal production and his conscription into the army.  

On November 17, 1944, the Ravelsberg near Würselen in Germany was littered with mines. It is here that Josef Mohren starts recovering the bodies of dead American soldiers. He ensured that they received an honorable burial. For him, they represented idealism and a steadfast commitment to freedom. In the first three weeks, he initially recovered 32 American soldiers, but eventually also 132 fallen German soldiers. Josef Mohren survived the war and became a special constable, with the aim of helping prevent any resurgence of fascism.