Part of the When they Cry series of visual novels, this is a murder mystery known and generally loved on OT. Or maybe I mean horror. Or possibly school comedy. It has an excellent anime series, although generally it is believed to be inferior to the game.
And did I mention the blood? There's a lot. (But you shouldn't watch it for that, but more for the mystery; otherwise you'd be disapointed)
GARsaka says hi. (Play the game/watch the anime to know what this means.... and the vid has a spoiler, how big depends on your progress in the anime/game)