As Simple As Snow -- Gregory Galloway
From As Simple as Snow:
Anna Cayne had moved here in August, just before our sophomore year in high school, but by February she had, one by one, killed everyone in town. She didn't do it all by herself--I helped with a few, including my best friend--but still, it was no small accomplishment, even if it was a small town.
If that first paragraph doesn't pull you in, I don't know what will. This is a must read. I loved it, started it a half hour before work, and was just itching to get back to it all day. I went home that night and devoured it. If I was still working at the store, I'd make them move it over to the "Suggestions for Older Readers" section and sell it to everyone that walked in the door.