The Cornwalls Vanish (previously published as The Cornwalls Are Gone) by James Patterson

Captain Amy Cornwall's family is missing. She'll do whatever it takes to bring them home. In her career as an Army intelligence officer, Amy Cornwall has seen haunting sights half a world away. None compare to the chilling scene at her Virginia home. It is empty. A phone rings with a terrifying ultimatum: locate and liberate an unnamed captive in forty-eight hours, or her kidnapped husband and ten-year-old daughter are dead. Now, and in open defiance of Army Command, Amy must employ every lethal tactic she has to save them. To succeed, she must discover not only who dispatched her on this mission, but why. Without her family, she's dead anyway.