A scene was shot in which Illeana drives back to her house with the old pick-up and a branch from a tree falls and breaks the windshield. It took several takes to get the shot, and apparently destroyed the last remaining windshields for the pick-up available anywhere in North America at the time. The scene was not used.
Donald Sutherland (with a full beard), Kiefer Sutherland's father, is used as a model picture in one of the sketches shown when Illeanna first explains the m.o. of the killer.
Despite the fact that the film is set in Montréal, Québec, the police officers are portrayed by French actors who do not have French-Canadian accents, but rather French accents from France. This would be like featuring Canadian actors to portray Texas Rangers.
The source novel's character equivalent to Illeana is James Costa, a British museum curator. Martin Asher's analog is Martin Arkenhout, a native of Holland. The prime settings of the novel are England and Portugal.
Illeana is a romanian name. Ileana written in romanian language. Variant of name Helen or Ellen, in romanian Elena.