Serial Superstition — David Archer

Sam and Indie are drawn back into another seemingly supernatural adventure when the widow of a recently executed serial killer comes across a list of the victims he had planned to kill but never got around to. When they start ending up dead in the same ways he was known for killing his victims, she asks them to help prove that it is the ghost of her dead husband committing the murders. Beauregard and Grace jump in to help. But even the spooks soon find themselves terrified at what they uncover—and even more frightened when Sam and Indie are targeted by the killer, and only the ghosts can save them.