Without Trace — Katherine John

Dr. Tim Sherringham goes out on an emergency call early one morning and vanishes on the way from his flat to the hospital. Without trace.
Daisy, his physician wife, is plunged into a nightmare of terror and doubt as she tries to discover what has become of her beloved Tim. With the support of her glamorous, wealthy in-laws Richard and Joanna, Daisy clings to a diminishing hope that her husband of six months will be found.
Local police officer Trevor Joseph investigates what looks like the work of a serial killer preying on unsuspecting motorists, and then realizes that what he faces is a far more insidious horror.