The Old Wine Shades : a Richard Jury mystery / Martha Grimes.

Enhanced descriptions from Syndetics:

The latest in New York Times bestselling author Martha Grimess Richard Jury mystery series
The dog came back.
This is a joke, right?
No, it isnt. . . . So do you want to hear the rest of it? Dumbly, Jury nodded.
The rest of it is told by Harry Johnson, a stranger who sits down next to Richard Jury as hes drinking in a London pub called the Old Wine Shades. Over three successive nights Harry spins this complicated story about a good friend of his whose wife and son (and dog) disappeared one day as they were viewing property in Surrey. Theyve been missing for nine monthsno trace, no clue, no lead as to what happened. Hes a fascinating bloke, this Harry Johnsonrich, handsome, unattached, and brainy about the esoteric subject of quantum mechanics, a field in which the vanished womans husband, Hugh Gault, excels: Hes an authority on string theory, which has some pretty funny notions about the nature of reality. Jury wonders, Is Harry Johnson winding him up? Or did it really happen? The dog did come backbut how? And from where? And when Jury investigates, all seems to be just as Harry described it. Until they find the body.
Praise for Martha Grimes:
One of the established masters of the genre.
Newsweek
Grimess] gift for evoking mood and emotion is as keen as her talent for inventing a demanding puzzle, and solving it.
The Wall Street Journal
Grimes] excels at creating a haunting atmosphere andcharacters both poignant and preposterous.
USA Today
Grimes is gifted at exploring the private, sometimes horrifying, yet utterly mundane thoughts of ordinary people.
San Francisco Chronicle