I have to give major kudos to Atty Eve and her "My Beautiful Suicide" books. There are three so far. They start off a bit slow in the beginning of book one, but then things pick up to epic levels. I suppose the best description I can give this book is "high school life" meets "vigilante" meets "the Manson Family," with elements inspired by the headlines from real life.
I've been into extreme horror for many years - from Clive Barker to Jack Ketchum and more - and it takes a lot to make me cringe - yet these three books do it. There are elements and scenes from these three books that sometimes make it very hard to continue, especially when you remember, these are just high school kids.
Highly recommended if you like disturbing horror on a realistic level. And if you have kids, you'll likely want to keep them on a tighter leash after reading these books.