He was a handsome and charismatic local minister; she was the church choir's beautiful soprano soloist. In 1922 they were found together, brutally murdered, along a secluded lane in New Brunswick, New Jersey—a popular spot for lovers' trysts. Each of the victims was married—to someone else. And although the police believed this would be an easy case to crack, it became one of the most high-profile unsolved crimes of the decade.At first, the primary suspects seemed obvious—the betrayed wife and husband of the slain lovers. The minister's wife was one of the town's wealthiest and most socially prominent citizens; the soprano's husband was a man of modest means, working as the church sexton. But as the investigation progressed, new suspects were uncovered and key eyewitness testimony was found to be false—deepening the mystery surrounding the murders.Combining elements of adultery, wealth and social prominence, revenge, a long and colorful list of...