They Fade and Die, by A. K. Adams
Jane Lester from Yorkshire takes a gap year after sixth form. She loves children and takes up a position as a nanny to a family in San Francisco.
The parents of the children, Teresa and Ryan, are a professional couple. Howard is a Cardiac Surgeon and Amanda a practising clinical psychiatrist.
Jane becomes concerned when she reads a newspaper headline about a headless torso found in the woods north of the city but Amanda reassures her it's nothing to worry about.
Teresa and Ryan are lovely children but Jane grows to question some of Ryan's comments about his parents and the previous nanny, Caroline, who left the role under a cloud.
On the other side of the city Jake Bauer has gone missing and SFPD are having a difficult time tracing him.
Meanwhile Jane meets Andrew and they become friends. He's handsome and talented, but after a while she begins to wonder if he's telling the truth.
The headless torso is eventually identified and Amanda is horrified to discover that a friend of hers is implicated.
Eventually police find the missing person . . . in disturbing circumstances.