The Servants of Twilight

I recently read a mystery novel called The Servants of Twilight by Dean R. Koontz. Joey Scavello, a six-year-old boy, is the main focus of the book. His mother, Christine Scavello, owns a gourmet shop in Newport Beach, California. Together, the two live in Costa Mesa, a city near Los Angeles. The Church of Twilight, headed by a supposedly psychic woman named Grace Spivey, is the main force against Joey Scavello. Charlie Harrison is a private detective who helps the Scavello family evade the clutches of the members of The Church of Twilight, who are called The Servants of Twilight. It begins on a sunny afternoon in 1985 in the parking lot of a Costa Mesa mall. Christine Scavello and her son are walking to their car when an old woman appears and begins to shout, "He must die!" toward Joey, and rants the phrase, "Don't you know what he is?" Later, they see the same woman outside a window at their house and then she calls them on the phone several times, again saying that Joey must die. It is then that they decide to hire a private investigator. They go to the office of Charlie Harrison and he immediately gives them two bodyguards and a man to keep watch on their house. A while after they get home, two men come with guns, invade the house, and kill the bodyguards. Joey and Christine manage to escape, but know they must go to another city to be safe. After much research, they find that the people following them are from The Church of Twilight, lead by the old woman who confronted them at the mall, Grace Spivey. Eventually, they travel with Charlie all the way from Los Angeles to the mountains of Sacramento, trying to get rid of the "Twilighters". However, every time they stop in a city to rest, the "Twilighters" show up, again attempting to kill Joey. Grace Spivey uses her psychic powers to locate the boy. She believes that six-year old Joey is the antichrist and the son of the devil. She thinks he will rule the world for a thousand years if she does not kill him. The group ends up at Charlie's cabin in the mountains near Sacramento and they believe they are safe from the ten members