Why one decision from Deeks’ past remains the most haunting moment of his NCIS career.
Throughout 13 seasons of NCIS: Los Angeles, Marty Deeks stood out as the loyal, witty, and often underestimated link between the LAPD and the elite NCIS team. Played by Eric Christian Olsen, Deeks brought charm, depth, and emotional complexity to the series — especially when it came to his romantic arc with Kensi Blye. But even the most beloved characters carry secrets, and for Deeks, one of them turned out to be his most devastating mistake.
⚖️ The Episode That Changed Everything: “Internal Affairs”
In season 7, NCIS: LA takes a sharp and personal turn with the episode “Internal Affairs.” Deeks is arrested, accused of murdering his former LAPD partner, Francis Boyle — a man with a long history of abusive and corrupt behavior. The accusation is deeply personal, and the entire NCIS team rallies around Deeks to prove his innocence.
By the episode’s end, Deeks is cleared. Case closed? Not quite.
In a gut-wrenching final scene, Deeks quietly confesses to Hetty Lange that yes — he did kill Boyle. But it wasn’t out of vengeance. It was to protect a vulnerable sex worker whom Boyle had brutally abused.
🤐 The Weight of the Secret
Deeks’ decision to lie — not just to authorities, but to his own NCIS family — becomes his biggest and most consequential misstep. Yes, his actions were rooted in a desire to do good, but covering up a murder, especially when your entire team risks their careers defending your innocence, is a betrayal on many levels.
The fallout? Complicated.
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Hetty already knew. In classic Hetty fashion, she reveals she had long suspected the truth — and still kept him on the team.
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Kensi also knew, and later admits to having carried the burden of his secret alongside him.
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Ellen Whiting, an Internal Affairs investigator, later learns the truth too — and it nearly costs Deeks everything again.
🕵️ A Secret That Refuses to Stay Buried
The ripple effect of Deeks’ confession doesn’t end in season 7. In season 8’s “Under Siege,” he admits the truth to Whiting while she lies critically wounded. When she survives, she doesn’t forget — and returns in season 9 to blackmail Deeks into cooperating with an investigation. The guilt, tension, and consequences continue to mount.
In retrospect, Deeks’ choice to keep the murder secret for so long only deepened the emotional and professional risks he faced. The longer he stayed silent, the more dangerous the fallout became.
❤️ Why Fans Still Forgive Him
Despite the severity of his actions, fans of NCIS: LA have largely continued to stand by Deeks. Why? Because he’s always worn his heart on his sleeve. His intentions, though flawed in execution, were rooted in empathy — protecting someone who couldn’t protect herself. That moral gray area, along with Olsen’s layered performance, made Deeks’ storyline one of the most human in the entire franchise.
🧨 The Bottom Line
Marty Deeks’ confession to killing Francis Boyle wasn’t just the character’s biggest mistake — it was a turning point for NCIS: Los Angeles as a whole. It peeled back the procedural polish and revealed the messy, uncomfortable truth that sometimes even the heroes carry secrets that could destroy them.
And yet, it’s that very complexity that made Deeks more than just a sidekick or comic relief. It made him unforgettable.
Catch all episodes of NCIS: Los Angeles on streaming, and relive the moment that changed Marty Deeks — and the team — forever.
