Stay Behind: NATO's Shadow Warriors (2014)

For the first time, a member of the secret BND partisan force "Stay behind" reports on his mission during the Cold War. "Dieter Gerlach," as he was code-named, was supposed to set up resistance groups in the enemy's rear in the event of a Soviet occupation of the Federal Republic. The BND partisans practiced explosive attacks until the 1970s, and later radio and smuggling operations in occupied territory. When it became known in 1990 that the Italian partner organization of "Stay behind" was involved in terrorist attacks, the German government initially denied the existence of the partisan network.