This is probably the most absurd movie I've ever seen. The whole time I was wondering if it was some kind of parody.

What are the chances of meeting so many psychopaths in one city and a special investigative unit made up of the stupidest cops?

The lead female cop in the leather coat comes across as the most badass, but when she meets the killer she shits her pants and lets him get away.

Every secondary killer basically kills with a hammer.

Poor silent kid is kidnapped by psychopath 1, within 24 hours he gets to psychopath 2, and meanwhile psychopath 3 buries psychopath 1. Seriously?

The body is hanging in the woods 2 meters above the ground in a tree with no lower branches and it's closed as a suicide.

And there's plenty of nonsense like that.
Whoever wrote the script probably drank a lot of soju, otherwise I can't explain it.