Judgment Prey (Prey 33) by John Sandford

Lucas Davenport and Virgil Flowers team up to crack an unsolvable case in this thrilling new novel by #1 New York Times bestselling author John Sandford.
When federal judge Alex Sand and his two young sons are shot in cold blood at their family home, the brutality of the murders leaves their wealthy St. Paul community reeling. There's no shortage of people with a vendetta against the judge, but the collapse of a major charitable donation he had planned complicates things further, leaving the money in limbo and all eyes on his grief-stricken widow.
As public pressure mounts and both the local police force and the FBI hit one dead end after another, it isn't long before Lucas Davenport and Virgil Flowers are called in. The duo are determined to chase down every angle and every theory until they figure out who killed the Sands. But when they find themselves stonewalled by the most unlikely of forces, they begin to wonder if each misdirection might actually lead them closer to the truth . ..