The other prisoners, such as Wing Commander Tony Wragg considered him to be a stool-pigeon. He was suspected of betraying Vic Roberts and L.A.C. Laxton during their escape attempt. Hollweg had seen them blackening their bodies just before they broke out of the barbed wire.
Later, Bertie and Ginger overheard Hollweg reporting the activities of the prisoners to von Stalhein, thus confirming Wragg's suspicions.
When alarm was raised during Biggles' attempt to free the prisoners, Hollweg ran towards Christophe's troops but was shot when they thought he was trying to escape.