Harry Riebauer

A strangler is loose on a British estate, and he not only strangles his victims but brands an "M" onto their foreheads before he decapitates them. (imdb)

Police try to track down a hooded serial killer who murders his victims with a combination of acid and poison gas. (imdb)

ir John (Siegfried Schuerenberg) and Inspector Craig (Hansjoerg Felmy) of Scotland Yard travel all over the city of London in their attempt to unravel the evidence needed to put a big drug-smuggling organization out of business. There are certainly enough corpses to provide clues, as the gang they are pursuing is unusually desperate and ruthless. (allmovie.com)