Rapture by Thomas Tessier (1987)
Jeff Linker is not a nice man. We first meet him after a sexual redezvous with Diane, whise teen-aged voice complains
Daddy's always working," she went on in that little girl tone, her face a mild pout.
"And my mother can't stand to be around the house. she's out somewhere with her
friends every day."
After promising not to tell her parents, Diane lets Jeff go.
We then learn that Jeff is in his late thirties. That's when his creepiness level soars.
Jeff is a driven man. He and a friend started a computer company in Southern California and after twenty years of ninety-hour days, he is rich, successful, and insulated. He has no friends, no social life, and his home is drab and utilitarian.
When his father dies, Jeff heads to his home town in Connecticut to settle his affairs. Driving through town he passes the Slaton house and sees a for sale sign on the lawn. He knew the Slaton family very well in high school. The daughter, Georgianne, was his best friend and secret crush. They would double through their teens, she with her constant lunk of a boyfriend, he with a number of meaningless girls he saw, and always in the background was his unstated desire for Georgianne. They had lost contact after high school; Georgianne went to college in Boston and Jeff went to UCLA three thousand miles away.
Jeff begins to fantasize about his high school crush. He convinces himself that he could at last be with her. Tracking her down, finds that Georgianne is married and has a seventeen-year-old daughter who strongly resembles the young Georgianne he knew. As his obsession grows, Jeff decides that Georgianne cannot be happy; she must feel trapped in a small town with a boring clod of a husband. He knows that, given the chance, Georgianne will drop everything to be with him. Forever.
As he arranges to infiltrate her family, he becomes surer that he and Georgianne are meant to be together, no matter how many obstacles between them he must eliminate. Coldly, he begins to set his plan into motion.
Oh. Remember Diane? The teenage girl Jeff was having sex with at the beginning of the book? Well, Diane is not a teenage girl. She's a hooker and Jeff is a regular client. His sessions with her are imaginative fantasies of sex with a young Georgianne. The creepiness gets ramped up.
This is a strong psychological novel about an obsessive sociopath, reminiscent of Robert Bloch's The Dead Beat, of Jim Thompson's The Killer in Me, and of much of Stephen King's work. Strong stuff and not for everyone, but if you are looking for an unrelenting chilling read, Rapture will meet your criteria.