Although emaciated veteran character actor Gibb McLaughlin is billed above the title in the title role as the late Edgar Wallace's "famous criminal investigator" J.G.Reeder in this slick, cynical little potboiler with germanic sets and lighting (and a very busy music score), he actually takes a back seat for much of the film as various other characters busy about engaged in a variety of illegal and mean-spirited activities before it all goes wildly over the top for the climax (again reminiscent of an old 'Dr Mabuse' adventure) while Reeder himself keeps watch in his own words "at a safe distance".
Review of Mystery of Room 13
