City walls
(Book)

When a search for a fugitive embezzler leads Amos Walker to Cleveland, fellow visitor Emmett Yale, a leading figure in the electric-car industry in Detroit, hires the private detective to investigate the death of his stepson, Lloyd Lipton, in a random freeway shooting. Yale believes Clare Strickling, a former employee, arranged the killing to silence Lipton, who is suspected of selling illegal inside-trader information to Strickling. Walker shadows Strickling to a private airfield, where he believes his quarry has made arrangements to fly out of the country, and witnesses Strickling’s killing—by way of a murder weapon unique to Detroit. From there, the trail twists and turns through Major Jack Flagg, an elderly barnstormer, Palm Volker, the attractive aviatrix who runs the airfield, Candido, a surly maintenance worker employed by Palm, and Gabe Parrish, the retired boxer in charge of security at Yale Mobility. Naturally, all have secrets to keep; and naturally, discovering them can be detrimental to Walker’s health.