Plot synopsis: Enemy secret services from the West had used modern technology for the "cold war", i.e. the confrontation with the Eastern Bloc, and developed a device called COMMINT 3-72. Its nickname was "Radiokiller". This weapon was not much bigger than a soccer and could be easily camouflaged on the territory of the GDR, for example as a fieldstone, the remains of a wall or a lump of earth. These enemy objects were inconspicuous on the outside, but packed with complicated inner workings, i.e. highly sophisticated microelectronics.