What you break - Reed Farrel Coleman

Gus Murphy and his girlfriend Magdalena are put in harm's way when Gus is caught up in the distant aftershocks of heinous crimes committed decades ago in Vietnam and Russia. Gus's ex-priest pal, Bill Kilkenny, introduces him to a wealthy businessman anxious to have someone look more deeply into the brutal murder of his granddaughter. Though the police already have the girl's murderer in custody, they have been unable to provide a reason for the killing. The businessman, Spears, offers big incentives if Gus can supply him with what the cops cannot: a motive.