"The Home Front" by Charles Ardai

From: Death Do Us Part ed. Harlan Coben, Little, Brown, and Company, 2006.

Hired to enforce U.S. rationing laws during World War II, a P.I. tricks a garage attendant into selling him four gallons of gas instead of the allotted two. Back on the road, the well-meaning attendant cuffed beside him, the P.I. is blindsided when a car swerves into his path. The attendant dies in the resulting fire, and the P.I.'s livelihood goes to hell.

Once back on his feet, the P.I. closes his office and walks aimlessly yet uncannily finds himself back at the same garage. Against his better judgment he stays to help the attendant's mother, assuming another man's identity, hoping no more of the past catches up to him. But of course, it does.

The P.I.'s voice is classically hardboiled, driving the story at just the right pace to give its twists full impact.