Part of the Instruments of Death series, Jackhammer builds from elements in Pickaxe, Icepick, and Meat Cleaver. Rat and George join detectives Andy Sinnott, Troy Nolan, Connie Kelly, Rich Pearson, Del Conklin, and state police lieutenant Dave Mullins, plus FBI Special Agent Lester Cartwright and a team of federal investigators, in a search for dismembered bodies buried beneath the streets of Riverdale. Bob Irwin wants to cut a deal. Irwin says he knows where the mob buried dozens of bodies. Irwin promises to tell all in exchange for immunity from prosecution and forgiveness of penalties and fines the IRS impossed on Irwin's illegal and unreported transactions. Can Andy keep Irwin alive long enough to unearth all the bodies? Can Andy stay alive himself? Bob Hunter and Bro team with Andy, Connie, and Arnold to sniff out clues, and Forensic Pathologist Sally Nolan calls upon the expertise of forensic anthroplogists to help solve the mystery.