Obsession — Jonathan Kellerman

Tanya Bigelow was a solemn little girl when Dr. Alex Delaware successfully treated her obsessive-compulsive symptoms. Now, at nineteen, Tanya returns with a curious request: that Delaware investigate her aunt's deathbed confession of murder. While Delaware doubts that Patty Bigelow was capable of such a horrific act, he agrees to look into the matter. Armed with only the vaguest details, Delaware and LAPD detective Milo Sturgis retrace Patty's and Tanya's nomadic and increasingly puzzling life. Then a very real murder tears open a terrifying tunnel into the past, where secrets--and bodies--are buried. As the tension mounts, Delaware and Sturgis uncover a tangled history of desperation, vengeance, and death--a legacy of evil that refuses to die.