NCIS: Los Angeles Episode 4.08 Collateral

NCIS: LA investigates the death of Victor Potter, an ex-CIA operative who was killed by a controlled explosive placed inside of his favorite lighter. Potter made a lot of enemies over the course of his CIA career, and he also made some consulting on spy movies and video games, making the list of possible killers extremely long. Video from a recovered hard drive points the team to an escort service, which was hired out by a known hitman wanted by every major law enforcement agency in the country. However, when their chief suspect is killed by an unknown assailant and Hetty and Granger go off the grid, Callen knows something isn't right. Callen and Sam find a picture of Hetty with Granger, the deceased Potter, and another ex-CIA spy, all of whom worked a variety of covert missions in the past. When the fourth operative's body is found and Hetty's safehouse is compromised, Callen knows the team has to find her before the mystery assailant does. After a tense shootout at the safehouse, the killer is revealed to be Fatima Kahn, the daughter of a terrorist that Hetty's former team killed many years ago. In the end, Kahn and her cohorts are killed, leaving Hetty's list of mortal enemies one name shorter.