NCIS: Season 7, Episode 17

7 - 17: Double Identity

Gibbs and the team investigate the shooting of a Marine and uncovers more to his life than anyone would have ever imagined. The Marine had been declared MIA after a reconnaissance mission in Afghanistan, somehow obtained millions of dollars, and married another woman under a false identity. The victim's commanding officer reveals that in Afghanistan, they stumbled across a money cache. The victim took the money for himself and disappeared. The team then deduces that a private investigator the commanding officer hired to find the victim was the shooter, as he intended to blackmail the victim. It is also shown that Ducky's mother has passed on, sometime in 2010.