The question of dual identity or split personality is most famously explored in two great 19th-century Scottish novels, Hogg's The Private Memoirs and Confessions of a Justified Sinner and Stevenson's Dr Jekyll and Mr Hyde. The theme has been getting quite an outing in Hollywood movies recently. The latest example is the slick thriller Mr Brooks, directed and co-scripted by Bruce A Evans, a film-maker more associated with mindless comedies like Honey, I Shrunk the Kids than with serious clinical matters.

Not that his convoluted tale of the Portland, Oregon, Chamber of Commerce Man of the Year Earl Brooks (Kevin Costner) is to be taken seriously. Earl is a wealthy, happily married box manufacturer by day and an ingenious serial killer and master of disguise by night, popularly known as the Thumb Print Killer. His closest companion is his demonic doppelganger Marshall (William Hurt) who, unseen by others, is constantly egging him on and justifying his crimes.

Costner as the ordinary Joe addicted to killing and Hurt as the Mephistophelean tempter are a compelling social and psychological casebook duo. The movie, however, becomes exponentially wilder as it proceeds. First, a nutty voyeur takes incriminating pictures of Brooks murdering two exhibitionistic lovers having sex and blackmails him into taking him along on the next spree. Then ace homicide detective (Demi Moore) pursuing the Thumb Print Killer is being followed by the Hangman, a serial killer she's put away who's now escaped.

Next thing, Brooks finds that his spoilt daughter has taken a lethal hatchet to a fellow student at Stanford, forcing dad to make the murder look like the work of a serial killer. There is something truly demented about Mr Brooks. It's less Zodiac than Taurus in a china shop.