Find That Book

The book I'm looking for is something I read maybe 8 or so years ago. I believe that the book was an adult novel as it was something I got from my mother's bookshelf and had it a pretty "heavy" sex scene in it as I recall, so I don't believe it was something I got from school, being about 13 at the time.

What I can remember from the plot:
A single man gets custody of his teenage son after the boy's mother dies. If I recall correctly this is either the first time they're meeting or the first time in a long while. The boy doesn't know his father at all and thinks him odd, mostly because of his allergy to the sun. Strange things are going on around town like people going missing and being murdered and I suppose there are some Satanic aspects to these incidents because it's rumored around town that it's a vampire devil person or whatnot. The boy believes that his father is responsible and is a vampire, due to the sun allergy and being slightly odd. I can't remember if his father had done anything specific to make his son think he's a vampire or a killer. I believe the boy is just angry, sad, and dislikes his father a great deal for being absent. Anyway, the father teams up with a woman (love interest) and I believe that they are looking into some of the things going on around town. I don't remember anything about the woman or why the two of them are investigating together or at all, but I do remember he's spending time with this woman. The boy meets a girl and I don't remember much about her except that she wears different colored tights or something like that and gives the boy half of her sandwich when they meet. It turns out that the killings and whatnot have been done by a group of "satanic gothy" type teens who are being manipulated by a man. Now, I can't recall if this man who is doing the manipulating is an actual vampire or just a creep. I do remember that the group of teens kidnap the girl that the boy had become friends with because she's a virgin and they're going to sacrifice her or something and the evil man is going to drink her blood. The boy is injured, I believe it's his ankle that gets broken, and he's being held hostage and during this time I believe he sees his dead mother's ghost or something and talks to her.

That's all I can recall about the book, sorry if it's a bit long winded but I wanted to include as much as I could remember. Hope someone can help (: