Jason Costello takes a key from his pocket. He turns it in the lock of safe deposit box No. 899 at the Eastern Bank in Saugus, Massachusetts. He pulls the box off the shelf and carries it into a nearby room.
Al Zani and Shawn O'Neil crowd around him. The three men are New England law enforcement to their core: Costello is a young special agent in the FBI's Boston office with a reputation as a skilled interviewer. Zani is a lieutenant who has spent decades with the Massachusetts State Police. O'Neil is a state trooper; he's the one who traced this key to a tiny bank branch, bringing them here on a cold day in January of 2009.