The Nesting Dolls — Gail Bowen

Just hours before her body is found in a car in a parking lot, a young woman hands her baby to a perfect stranger and disappears. The stranger is the daughter of Delia Wainberg, a lawyer in the same firm as Joanne Kilbourn's husband. One close look at the child suggests that there might be a family relationship, and soon the truth about the child Delia gave up for adoption years ago comes out. The boy must be Delia's grandson. Then his mother is found dead, sexually assaulted and murdered. Not only is there a killer on the loose, but the dead woman's partner is demanding custody of the child.