When the police force in a provincial South Korean town is unable to solve a spate of strangulations, a detective is summoned from Seoul. Initially he mocks the methods of his country counterparts, only to become as frustrated as them over the lack of tangible evidence.
Between 1986 and 91, South Korea's first serial killer raped and murdered ten women. He was never caught but, rather than dissipating the suspense, this knowledge actually heightens the tension and focuses the attention on the pursuing quartet and the frustrations they endure during an investigation almost bereft of clues.
In particular, Bong Joon-ho plays on the rivalry between Song Kang-ho's swaggeringly doltish local cop and the scruffy, but more considered, city inspector (Kim Sang-kyung). But instead of relying on macho confrontations, Bong contrasts their approach by employing the same macabre humour with which he depicts the incompetence of the forensic units and the scurrilous sensationalising of the press.
He makes equally atmospheric use of the sombre landscape with its diverse ditches, alleys and tunnels and the pouring rain that accompanies the crimes, as well as the outbursts of intimidatory violence designed to scare the suspects into confessing - making its ambiguous ending all the more courageous and curiously satisfying.
Shifting the focus away from the crimes and onto the desperate measures to detect them, this is a compelling mix of docu-dramatic realism and stylised character study.