I'm trying to remember a teen book I read a while ago, it was about an Indian family - the mum died and they moved from Birmingham? to London and the girl made friends with 2 boys from her new school - the three of them were misfits and the story was set over one summer. The girl ended up killing one of the friends, I think he was called Dennis. It was such a brilliant book and I think it maybe had summer in the title.