The Neighbors

The Neighbors is a 2012 South Korea mystery thriller film starring Kim Yunjin in the lead role. In the film, residents of an apartment building suspect that one of their neighbors may be a serial killer responsible for the murder of a residing family's daughter. As the victim's stepmother investigates, the killer begins to target another young girl.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.