The Finisher (A Detective Peter Diamond Mystery)

"Detective Peter Diamond is tasked with crowd control on the raucous day of the race--and catches sight of a violent criminal he put away a decade ago, and who very much seems to be up to his old tricks now that he is paroled. Diamond's hackles are already up when he learns that one of the runners never crossed the finish line and disappeared without a trace. Was Diamond a spectator to murder?"--