Book, Tainted Lives by Mandasue Heller.

Blurb Reads: -

At the age of Seven, Sarah Mullen is put into care by her drug-addicted mother. Trying to live with the rejection is bad enough, but no one could have prepared her for the pain that was yet to come.

Harry Shaw is the boy everyone loves to bully, the kid whose mother locked him in a cupboard so she wouldn't have to look at his ugly face. When he meets Sarah for the first time, a friendship is instantly forged.

Then into their lives comes Vinnie Walker. A good-looking, calculating thirteen year old. Rejected by his own mother, this is Vinnie's last chance to change his ways.

I could not put this book down. I you like Martina Cole then Mandasue Heller is another author you need to get to know