Der Henker von London on AllMovie

This quirky crime thriller stars Hansjörg Felmy as an intrepid Scotland Yard inspector tackling two seemingly disparate cases. He is officially assigned to investigate an underground society of vigilantes who take the law into their own hands, trying criminals in their own "Star Chamber"-style kangaroo court. On his own initiative, he is also pursuing a serial sex-killer who decapitates his victims. Felmy's dogged devotion to this case turns out to be personal, since his sister was among the killer's victims. The vendetta eclipses all other concerns, as the inspector even uses his own fiancee (Maria Perschy) as bait to trap the madman -- who suddenly falls into the clutches of the hooded vigilantes and is whisked away for a speedy trial. No prizes will be issued to viewers who guess the identity of the judge. This German production was also released as The Mad Executioners.