Grave Secret by Charlaine Harris
When she was 15, Harper Connelly was struck by a bolt of lightning, which left her with a spiderweb of red over her body, headaches, and episodes of weakness. Sometimes her right hand shakes. And she can find dead people. It's taken a while, but at last Harper's pretty happy with her life: she's making a living, using her unique talent to help people, and she's got a lover - her stepbrother Tolliver. That creeps some people out, but though they grew up together, and got each other through the real bad times - their parents' drug-use, the abuse, the disappearance of Harper's elder sister Cameron - they're not blood relatives. Then Tolliver's dad arrives on the scene, seeking forgiveness for the sins of their youth, and the police get a tip-off that after all these years, Cameron's been spotted in a mall. With all this going on Harper realises life is getting a little complicated, but she doesn't expect those complications to include Tolliver getting shot, or watching a cop die taking a bullet for her. Harper can find dead people, but now it's clear someone wants her dead ...