Walking Shadow. The Darkworld Series, #2

Ashlyn has found a new home in Blackstone, but when a flood of mysterious grave robberies hits the town, the local sorcerers are convinced it signals a new sign of demonic activity. As a rogue sorceress with no idea where her magic came from, Ash is a prime target for suspicion. The trouble is, what Ash does know might just get her killed. When Leo's guardian is murdered in suspicious circumstances, all signs point to a connection with the recent grave robberies.
 Ash determines to help him find out the truth, but it isn't long before events are spiralling out of control. The dead are rising from their graves, and the barriers around Blackstone are threatened by a demon which looks exactly like Ash herself. With the magic police on her tail, it's up to Ash to stop the demon before her own dark magic condemns her to death for crimes she never committed.