A neighbor finds the body of a tortured Marine lance corporal, hanging in his garage; Gibbs and company investigate. When Gibbs and Tony seek to question a recently retired Marine, they find Fornell inside the retiree's home; Fornell says that the Marine is the FBI's key witness in a murder trial; McGee finds that Fornell's defendant is one of the most notorious criminals on the East Coast. Another Marine dies after enduring torture. The retiree-witness leads Gibbs and Fornell on a chase, then they question him again. Abby finds crucial evidence against the gangster; Fornell, Gibbs, and the gang connect the dots, and a confrontation takes place on a sidewalk and closes the case.