L'Énigme des sables(1988)

A team of amateur filmmakers sets off, camera in hand, to the south of Morocco. During their stay, one of the members of the group, Fanette, a vulgar vampire, is murdered. The Moroccan police do not find the culprit, and Paris takes over the case. The inspector in charge of the investigation decides to view all the "works" made on site, in the presence of their author.