At seven o’clock in
 the morning on
 February 11, 2010, a man drove to the well-heeled community of Bellaire, in the heart of Houston. He turned onto South Third, a quiet street dotted with million-dollar homes built on small lots, and stopped in front of a two-story, five-bedroom stucco house with a swimming pool in the backyard. It was the residence of Jeffrey Stern, a successful personal injury lawyer; his wife, Yvonne; and their fourteen-year-old daughter and twelve-year-old son. The driver paused for a moment and studied the house. Then he pulled out a handgun; fired two shots, one of which went through the living room window; and drove off.

Jeffrey was out of town, but Yvonne and the children were sleeping upstairs. She was wearing earplugs and didn’t hear a sound. Her daughter, who was awakened briefly, thought a painting had fallen from a wall. But a neighbor who did hear the gunshots called the police. The Sterns were completely bewildered when officers arrived at the house. All they could imagine, they said, was that some teenagers from another neighborhood had shot at the house as part of a prank drive-by. Two months later, at ten-thirty at night, another man with a gun drove to Bellaire. He got out of his van, walked up to the Sterns’ home, and rang the doorbell. Yvonne went to the door and her son followed behind. She was 52 years old, a beautiful woman with flawless skin, gleaming dark eyes, and glossy brunet hair cut to a shoulder-length bob. The man saw her through a glass pane, smiled, and fired at her. Yvonne pressed herself against a wall, and the bullet missed her and her son by inches. The man sprinted to his van and sped away.

Once again, the police were unable to find any leads. Jeffrey, a slim, bespectacled 54-year-old with carefully groomed silver hair, hired a security company to install bulletproof glass in all the windows, erect iron gates around the front door, set up surveillance cameras, and place floodlights on the roo...