In a movie I saw a few years ago, there was a scene where a child was kidnapped at night, in the rain. In another scene, a man hacked a bunch of young boys to death in a cellar and buried their bodies in a mass grave. The grave was later discovered. The setting might’ve been America or some European country, like England. It was also old-timey, maybe 1930s or so.
Sounds like Changeling.
http://m.imdb.com/title/tt0824747/