Riot Act — Zoe Sharp

Charlie Fox is dog-sitting for a friend, only to find that the friend's housing complex is being terrorized by violent gangs. Desperate and frightened, the residents have hired a freelance security firm, whose bully-boy tactics aren't a whole lot more appealing. With her bike on hand and a big dog by her side, Charlie is more than able to take care of herself, until a ghost comes calling a ghost from Charlie's very bad old days.