Im Nest der gelben Viper (1966)

South Africa is in turmoil. A secret underworld organization calling itself the “Yellow Viper” terrorizes the port city of Cape Town with robbery and murder. Using a viper’s deadly venom, they kill dangerous witnesses and adversaries. Interpol is asked for help, and Washington sends—once again, of course—its best man, FBI agent van Dongen. He is to infiltrate the criminal organization, expose its boss, and finally bring him to justice. The criminals are under pressure because they recently had one of their own, Carlo, murdered, allegedly for committing treason. Shortly beforehand, Carlo had sent a letter said to list all the names of the “Viper” members. When van Dongen’s cover is blown after his successful infiltration, he receives unexpected help from the gangster boss’s girlfriend, who gets him out of trouble. The beautiful young woman, however, pays for her betrayal with her life. Nevertheless, after two chases—one on the water and one on land—the American succeeds in cutting off the snake’s head. He has a personal score to settle with the gangsters: his father, a scientist, was murdered 15 years earlier on the “Yellow Viper’s” orders.