Separately, well educated Detective Seo Tae-yoon travels from Seoul to assist with the investigation and when he arrives is appalled at how the investigation is being conducted.
The two men clash, unsurprisingly...
Set in a much less prosperous 1980s Korea, this is a tale of culture clash as much as it is a procedural crime drama. Only Bong Joon-ho's second movie it's already showing how he can mix comedy in with societal commentary and quite grim drama.
Methodical Detective Seo has to contend with things like officer Kim who wears heavy boots specially for beating up suspects, but has a soft cover he slips on them to avoid breaking the skin.
With mention of civil unrest and regular preparedness drills it shows a society accustomed to brutality not just from the local Police.
Tae-yoon seems to embody the change that is to come but in the end he too is drawn to violence. This is mostly done from the viewpoint of Detective Park who adopts some of the other's restraint but can't really set aside his notions of intuition.
Up there with the great crime dramas of Anglophone cinema this is highly recommended 9/10.