Interesting odd addition to the Edgar Wallace cycle of films, essentially British krimi filmed with German financing and, of course, Eddi Arent, this time playing a bad guy. The humor of the film is considerably dispelled by a streak of sadism that would be more fitting in a giallo. The cast is excellent, though, especially a nicely sardonic Granger and a very cute Hardy. Great Peter Thomas score and nice topical references to Blow Up as well.

The frequent murder method (gassing) used in the film, as well as the glee with which it's performed, did not go over well with German critics, for obvious reasons. That, coupled with the decline of the krimi genre, led to its lack of success at the box office in Germany.

Note: This film has never been released in English on DVD, and the last VHS release (from which this listing is taken) dates from 1986! Unfortunately it is cropped, which tends to detract from the experience. [May 2020: now revised from the Tobis widescreen German DVD].