Cold Eyes (2013)

at the core of both are a structured search for justice even if you have to go a little outside the law to find it.

While Cold Eyes seems more cohesive thematically with a believably menacing antagonist, The Beast seems a bit less heavy handed about the idea of Big Brother always right behind you.

both follow a special team of investigators that catch the worst bad guys.

Both movie has a beautiful female lead that is a detective.
Intense, action movies.
One has love triangle, the other one does not
Full of action pack

Both productions feature a similar way of investigating that involves tailing a suspect, Cold Eyes focuses more on blending in, while Nusumareta Kao on straight-up following

In both the police use very similar methods of investigation. Both have a rookie female detective as the main lead.

If you want some action, crime, thriller, investigation, and a detective story, you've got to watch this too.They go undercover. Almost the same plot but the difference is their main task. In cold eyes, they follow and get information while in hidden identity, they find information, go undercover and follow, get the evidence or retrieve the stolen item then catch the criminals. It is like watching a series of cold eyes movie. Expect the unexpected. The main character in hidden identity tries to seek revenge for his girlfriend's death. No love story except for the flashbacks.