Actually, I would give it 3 1/2. It could have been a 4, as it was an exciting story and well written, save for three things:
1. As in the past, the editing could have been better. On page 204 is the sentence, "Mom says she expects that they'll get there in shortly." This makes little sense. On page 249-250, a little girl has been playing with a flashlight, as the electricity is off, but, after a conversation, she goes "back to her video." Her video?
2. The author tried far to hard to make one character the "bad guy." I wanted to yell at her and say, "OK, I get it." In mysteries, when the bad things are pinned almost exclusively on one person, it is almost surely not that person.
3. About 2/3 of the way through the book, new characters were introduced, and it was clear one of them had to be the "bad guy."
Nevertheless, it was a fun read.