Cozzi originally wanted to call the film Il Ragno (The Spider) but it was changed to The Killer Must Kill Again by the producers.

It is based on the novel Al mare con la ragazza (translation: By the Sea With the Girl) by Giorgio Scerbanenco.

[2] Giorgio is a greedy adulterer who makes a deal with a serial killer (Michel Antoine) to dispose of his wealthy wife, Nora.

Unfortunately, a thrill-seeking young couple steal the killer's car with Nora's corpse in the trunk, ending up at a run-down seaside villa.

AllMovie called the film "too erratic for the general horror audience", but "offers just enough suspense and style to please patient giallo fans.