What movie is this scene from?

[moviefanatic]

Years ago I saw a scene on TV (I'm pretty sure it was a movie) of a girl taking a shower in a school locker room and a dark figure comes in. She gasps, but then says something like, "oh, it's you!" and starts taking to the unknown figure as if she knows him. And then as he gets closer to her, he takes out a knife and stabs her repeatedly. The next thing shown is her bloody face and blood going down the drain. Then the scene changes to two girls walking down the street talking. Does anyone know what film this is from?