The book focused on a teenage boy who comes home to find his home burning down. I remember parts of the book dealt with people and kids his age being mind controlled by having some type of black rock that touched their bodies. The rocks would be part of a belt and I remember there being large broadcast towers of the same material which would increase the intensity of the mind control whenever someone was near.
I remember the protagonist befriending a kid who was a similar age and I remember this kid was adept at throwing knives.
Sorry for the vague memory. It was a book we had to read in the fourth grade and I never bothered to look into it until a few years ago and was never able to find it.