Just before sunrise on Dec. 4, 2003, Jonathan Luna, a federal prosecutor from Baltimore, was found dead — sprawled facedown in a shallow creek next to his idling silver Honda Accord. The car was smeared with blood, and Luna had suffered dozens of small stab wounds around his chest and neck.

Nearly seven years later, the death of the 38-year-old assistant U.S. attorney remains a mystery, and not without controversy.