Jack Campbell (James Spader)

A final addition to the equation is Polly, the psychologist played by Marisa Tomei, who is treating Campbell for the effects the case are having on him. And, although the role was originally written for an older woman, once Tomei was cast, Polly’s character became dangerously involved in the case. “What was wonderful about Marisa,” says Charbanic, “is that she brought a youthfulness and vulnerability to Polly, and that makes us care for her fate as much as Campbell does.”

Equally significant was the casting of Spader in the role of Campbell. An actor who has frequently played unbalanced characters - like the role in sex, lies & videotape which brought him to prominence - he brought a vulnerability to the part which perfectly fitted the screenplay’s idea of a man drawn into a deadly game by an entirely unscrupulous opponent. “James is the kind of actor who is adept at playing idiosyncrasies,” says Niami, “so it made sense that he play an FBI agent who is troubled, burned out. He worked very hard on the script, dissecting it, talking with the FBI agents. He was totally committed to that character.”

Charbanic was equally impressed. “I’ve never seen an actor work so hard on his character,” he says. “He brought incredible nuances to the role.”

The Watcher was filmed in Chicago between October and December of last year since, as Elliot points out, “the city is another character in the film. We deliberately chose Chicago because it’s a big city but can look very impersonal. It’s totally believable that lonely young women can vanish without a trace and that a killer can hide so easily in plain sight.”

“Most of the exteriors are shot at night,” adds producer Christopher Eberts, “when the streets are filled with people. But you can get lost in the crowd. You could live in a six-unit apartment for several years and still not know any of your neighbours’ names.”

But shooting in the Windy City did put certain constraints on the production, despite its 75-day shooting schedule. “During the day we took over half of Chicago,” says Niami. “And at night, [the second unit took over] the other half. It was very ambitious. But we got it done. We started production in early October and had to be out by Christmas because of the weather conditions.”

Crucial to the achievement - and to the look of the film - was the contribution of veteran cinematographer Michael Chapman, who more or less created the modern urban thriller with movies like Taxi Driver. Chapman also knew Chicago inside out, having shot The Fugitive (for which he was Oscar-nominated) on location there in 1993.

Facing page, Marisa Tomei as Polly, the young psychologist assigned to treat troubled FBI profiler
Jack Campbell (James Spader, above).