A Walk Among the Tombstones (2014)

In 1991 Manhattan, Mathew Scudder, an off-duty New York Police Department (NYPD) officer, is unexpectedly caught up in an armed robbery at a bar where officers drink for free. Scudder guns down the would-be thieves, however one of his bullets inadvertently strikes a seven year old girl, killing her instantly. Shaken from the experience, Scudder quits the force, and spends the next eight years in Alcoholics Anonymous (AA) while moonlighting as a an unlicensed private eye.

One night, after an AA meeting, Scudder is approached by the brother of a man named Kenny seeking to employ the PI to locate his wife's killer. Kenny explains that his wife was abducted for a ransom, the kidnappers killed his wife after he paid the $400,000 ransom, cutting her up in small pieces before returning her in the dismembered state to Kenny. Reluctantly, Scudder accepts the job.

At a local library, Scudder meets an adolescent named TJ, who helps Scudder by locating information on the net concerning similar cases to Kenny's. Scudder eventually traces the kidnappers' MO, and meets a cemetery groundsman who discovered one of the victim's remains while fishing trash bags out of a pond. After trailing the groundsman back to his house Scudder learns that he was an accomplice for one of the murders, and has had trouble getting over his role in the homicide. The groundsman explains that he met the two men that Scudder is after in a movie store; both men apparently shared a fetish-like interest in death. Scudder learns one of the two men goes by the name Ray, but before he can glean any further information, the groundsman abruptly kills himself by stepping off the roof of his apartment building. Upon further investigation, Scudder determines that the two men he is after were at one point somehow affiliated with the DEA, and have been targeting drug dealers from whom to extort money.

In a residential neighborhood, Ray and his accomplice prepare to abduct another woman, however Ray waves the kidnapping at the last minute. As the two prepare to leave Ray observes the target's daughter leave a house, and retools their kidnapping attempt to take the girl. When Scudder learns of the kidnapping he has TJ bring a box or his old police equipment to the victim's house, and instructs the victim to refuse payment unless they can prove the girl is still alive, correctly guessing that the kidnappers will kill the girl regardless of whether the ransom is paid. Scudder lures Ray and his accomplice out by forcing them to pick up the ransom in person. After the ransom is paid, a shoot-out occurs, injuring Ray. Ray and his partner flee the drop site, unaware that in the ensuing shoot out TJ managed to sneak into their van.

At their safe house, Ray attempts to get medical treatment for his gunshot wounds, however Ray's partner elects to kill him instead. After TJ calls Scudder with the safe house's location, Scudder and his ad hoc team arrive, precipitating a brief struggle. Scudder's people successfully restrain the second man, at which point Scudder instructs TJ to return to his place. After offering Kenny the chance to turn him in or obtain his revenge, Kenny opts for the latter, but the restrained second man escapes and kills Kenny before he can fulfill his wish. Another struggle ensues between Scudder and the second murderer, which ends when Scudder shoots the man in the head at close range. As the police arrive to secure and the scene and wrap up the case Scudder then returns to his apartment.