The Chaser (film)

The Chaser is a South Korean thriller released in 2007 directed by Na Hong-jin.

Joong-ho is a dirty detective-turned pimp. When his girls begin to go missing, he assumes that they are being sold by another customer. After using his skills to track him down, he is brought to the police only to discover that the man, Young-min, is instead a sadistic murderer and has been killing his girls. To make matters worse, the police have to let him go after twelve hours if no evidence can be found and Young-min claims that he is holding one of Joong-ho's girls, Mi-jin, captive. Can Joong-ho find evidence in time to bring Young-min to justice and rescue Mi-jin?

Set to be remade by the people who brought you The Departed.

Tropes used in The Chaser (film) include:

Anti-Hero - Joong-ho is of the Type III variety. He's a pimp, not a particularly nice guy and treats his prostitutes poorly. Still by the end of the film it's clear he's become emotionally invested in saving Mi-jin and comes to care for her daughter.
Based on a True Story - Young-min is based off of real-life Korean serial killer Yoo Young-chul (who was a cannibal in addition to being a killer).
Bittersweet Ending - Young-min is brought to justice but not before bludgeoning Mi-jin to death (just after she manages to escape his lair). The end of the film implies that Joong-ho will look after Mi-jin's daughter.
Black and Gray Morality
Bound and Gagged- Mi-jin spends half of the film in this predicament.
Cruel and Unusual Death - Mi-jin's death is extremely gut-wrenching.
Gory Discretion Shot - Young-min's bludgeoning of Mi-jin is offscreen.
Freudian Excuse - Young-min is sexually impotent.
Hammer Time - Young-min's weapon of choice.
Hope Spot - A particularly excruciating example. After spending the bulk of the film bound and gagged, Mi-jin finally frees herself and makes it to a nearby store, where the store owner hides her. However, when Young-min arrives at the store, the owner unwittingly gives Mi-jin away. This results in Young-min murdering both the owner and Mi-jin.
Morality Pet - Mi-jin's daughter serves as this for Joong-ho.
Monster Misogyny
Police Are Useless
The Quiet One - Mi-jin's daughter
Serial Killer