The bodies left behind - Jeffery Deaver

When a 911 call from an isolated vacation house on Lake Mondac is cut short, off-duty county sheriff’s deputy Brynn McKenzie leaves her husband and son at the dinner table to investigate—and walks into a scene of true horror. A visiting Milwaukee couple has been shot dead. Brynn, quickly connecting with the lone survivor of the carnage, realizes the perpetrators—two professional criminals—haven’t left the crime scene. Unable to call for back-up, deprived of her gun and car, Brynn and her charge escape into the hostile wilderness in a terrifying cat-and-mouse chase. Will Brynn be the next victim?