Why was Callen's father arrested?
That was revealed on NCIS: Los Angeles Season 9 Episode 16 when the Diplomatic Security Service went to great lengths to build a false narrative.
With time running out quickly, Callen utilized every resource available to him, and that meant the team was along for the ride.
After some digging, it emerged that it was all part of an exchange for American photographers being held hostage in Iran.
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Paul Dailly is the Associate Editor for TV Fanatic. Follow him on Twitter.