Hour Game by David Baldacci

Two former Secret Service agents turned private investigators are drawn into a baffling serial-killer case in which recent murders appear to be recreations of a string of killings from years before; as they follow cryptic clues, unravel a network of lies and corruption, and confront painful personal secrets, they must outthink a meticulous, taunting killer who treats his crimes like a deadly game before more lives are lost.

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