Pedro Hernandez was a Mexican drug dealer responsible for murdering Leroy Jethro Gibbs's first wife Shannon Gibbs and their young daughter Kelly Gibbs which occurred while Gibbs was fighting in Desert Storm in or around 1991 with Gibbs later exacting his own revenge by killing Hernandez with the aid of his own rifle.
NCIS Season 3
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NCIS Season 13
Thursday February 14, 1991: Sergeant Tanner - (shot to death).
Monday February 25, 1991: The car shooting (three fatalities):