"After 30 years, Detective Jim Scharf arrested a teenage couple's murderer-and exposed a looming battle between the pursuit of justice and the right to privacy. When Tanya Van Cuylenborg and Jay Cook were murdered during a trip to Seattle in the 1980s, detectives had few leads. The murder weapon was missing. No one witnessed any suspicious activity. And there was only a single handprint on the outside of the young couple's van. The detectives assumed...