One afternoon in February 2007, a man walked across an icy parking lot to the front door of a police station in Merrillville, Indiana. Next to him was an officer, whose job it was to make sure the man actually went inside the station. The man was very nervous – there was a warrant out for his arrest on a drug charge, and he’d been brought here to get questioned and then processed. But he hoped he’d get to leave again right away, because he had information about a four-year-old murder case, and he intended on trading that information for his freedom. And he was sure this would work, since what he knew wasn’t just a tip – it was a bombshell. Still, his stomach was in knots as he took a deep breath and opened the station door.