This quasi-giallo was scripted by Ernesto Gastaldi and directed by Bitto Albertini, who was shortly to find some success with his black version of Emmanuelle, titled Black Emanuelle (the success of which was hijacked by Joe D'Amato, who churned out several sleazy sequels). In common with Gastaldi's other films of the early 70s, there is little discernible Argento influence, with the motive behind the killings being inheritance-related, and plot taking precedence over style and effect (and scenery taking precedence over plot). This latter emphasis can be at least partly attributed to the director, who seems far more interested in showcasing the exotic locales (the film was shot in several countries, among them Sweden and the US, with the second half being set in Africa) than in wringing any tension out of the script. A perfect example of this lack of interest (/talent) can be seen in a sequence where the film's 'hero', played by George Ardisson, is stopped by police while transporting the corpse of a recently-murdered woman (Janine Reynaud) in the front seat of his car. Lucio Fulci staged a similar sequence to great effect in Touch of Death (his last good film), but here Albertini stages the scene as a routine conversation between the policemen and Ardisson, generating no tension whatsoever. Looking through his filmography, it's clear that his fondness for filming in foreign climes far surpassed his interest in the thriller film.
The film itself is moderately effective (and my appreciation of it possibly hampered by watching it on a pan-and-scan DVD), but comes up short as a giallo by virtue of having too few potential suspects. In common with other early 70s Gastaldi films (The Strange Vice of Mrs Wardh, The Curse of the Scorpion's Tail), we see the killer in plain view early in the film, and the identity of the figure issuing their orders (with all of two potential suspects) is the mystery at its heart. The lead character is presented as a former mobster who has been banished from America for past misdeeds, but ultimately we see no real dark streak in Ardisson's character, and the gangster backstory is both lazy characterization and an excuse to set the opening half hour in New York's underworld, to little effect. Some of the internal logic fails to stand up to scrutiny also (a character walks away from an exploding car with only faint burn marks on their clothes, and a scene set in the great Luciano Pigozzi's New York apartment makes absolutely no sense on second viewing), so this is far from top-tier Gastaldi. If you have to watch one giallo which is set in exotic locales, don't watch this one.