The fourth installment of ex-NYPD captain Mahoney’s Brian McKenna series (Once In, Never Out, 1998, etc.): a chatty police procedural mostly featuring globe-trotting, good-guy cops talking away in restaurants and running up expense accounts. Avoiding the Hollywood-style car chases and slam-bang shoot-outs of his previous outings, Mahoney here pairs the fictional McKenna with real-life NYPD homicide detective Tom McKenna (“a pal” whom the author denies was an inspiration for the fictional cop) and other existing law enforcement personnel as he solves a gruesome Fort Tryon Park torture-murder whose victims are the daughter of a politically shrewd New York councilman and the son of a wealthy Virginia criminal lawyer with close ties to Congress. In his first meeting with Tom, Brian discovers that this killing, in which the female victim was gagged and whipped to death, is virtually identical to an unsolved case that has obsessed Tom for 18 years. The two soon find other cops, from California and Arizona to Costa Rica, with similar unsolved murders that all occurred in secluded, spectacularly scenic areas. Brian shares the belief of his cronies that they—re all the work of two men—one black, one white—who sell photographs and videos of their carnage on the snuff-porn market. Thanks to the technically illegal Internet wizardry of former NYPD cop turned sleazy p.i. Joe Hurley, McKenna & Co. track the killers across the country as they use their victims” credit cards. Meanwhile, Arthur McMahon, the wealthy Virginian lawyer, has let Brian know that he wants the murdering team to die, legally or illegally, and will spend any amount to make sure it happens. Exact and fascinating cop-insider material, as always from Mahoney, but without much action or suspense—and the ponderous explicatory dialogue is no help.