The documentation is lacking, but giving due attention to posters and lobby cards I was able to integrate the cast with four new actors (Dino Strano [this time credited as Dean Strano, together with Lorenzon in the image below], Tony Bland, Roman Magnino and Sergio Serghey) and especially to establish with certainty that the film was released in 1967 and not in 68 as it was believed.
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The vocals give some additional information about the plot; so we learn that the stinkers are seven and led by a Mexican. The protagonist, a doctor and a monk join the bunch of swine gradually. In one scene the sheriff ends up buried up to his neck as Garko in $10,000 Blood Money or John Phillip Law in Death Rides a Horse, and there is a very unusual and bizarre narrative element that seems to be of some importance, the disappearance of the gang leader’s hand-held fan!