It's been a while since I've read this, but all I can say is it was brilliant. I love this specific type of book, which is probably why I also loved "The Monsters of Templeton" so much.
The main character is researching Salem for her doctoral thesis when she finds out her grandmother's house needs cleaned up and sold before it's taken by the city for non payment of taxes. What she finds is way more than she bargained for, and she takes us along for the ride. Interspersed with the contemporary narrative are historical flashbacks. Read it, you won't be disappointed.