I’ve just finished Adolescence on Netflix, and I’m still thinking about it — so I had to dig in and answer the big question: who is the killer? If you’re wondering the same, we’ll go through how the show reveals the truth (yes, spoiler ahead).
What Adolescence Is About
Adolescence is a four-episode limited series that follows Jamie Miller, a 13-year-old boy who is arrested for the murder of his classmate, Katie Leonard.
Each episode is filmed in a single, unbroken shot, creating a tense, immersive experience.
From the start, the question isn’t just who, but why he might have done it.
Did Jamie Kill Katie?
Yes — the show makes it clear: Jamie is the killer.
Here’s how it plays out:
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In Episode 1, the police reveal CCTV footage showing Jamie stabbing Katie in a parking lot. That video is a turning point in viewers’ understanding.
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Jamie denies it initially, but later (in Episode 3) accidentally confesses during a session with a court-appointed psychologist, Briony.
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Meanwhile, Jamie’s friend Ryan is revealed to have given Jamie the knife — but Ryan claims he didn’t know Jamie would use it to kill. He’s charged with conspiracy.
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By the final episode, Jamie decides to change his plea to guilty, formally admitting responsibility.
So while Ryan plays a role in supplying the weapon, Jamie is the one who carried out the murder.
Why Did He Do It?
The show isn’t built as a twisty mystery — we’re shown from early on that Jamie did it. The real tension lies in why.
Here are key factors:
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Jamie is deeply insecure and becomes influenced by misogynistic ideas circulating online (the so-called “manosphere”).
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Katie had shared a topless photo to one classmate, which was then circulated and ridiculed. Jamie claims that after Katie mocked him, he felt humiliated.
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He believes Katie called him an “incel” (involuntary celibate), which in his mind further justified angry feelings toward her.
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The creators purposely avoided giving Jamie a “bad home life” or obvious trauma — the point is that even kids from seemingly stable backgrounds can be radicalized.
It’s a bleak exploration of how isolation, online extremism, and peer pressure can combine in dangerous ways.
4 Interesting Facts You Might Not Know
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All four episodes were shot as single continuous takes (one uncut shot each).
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The series is not based on a single real case, though it was inspired by a rise in knife crime among youth in the U.K.
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Owen Cooper, who plays Jamie, became the youngest male actor to win a Primetime Emmy for his performance.
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The creators intentionally didn’t include a traditional courtroom trial in the show — the focus is on internal conflict, public reaction, and family trauma instead.
My Take
Watching Adolescence felt like peering into a modern nightmare. It haunted me long after the credits rolled. I found myself wrestling with how much of our youth’s struggle stems from online communities, isolation, and expectations of masculinity. I don’t think I’ll ever look at social media the same way again.
In short: Jamie is the killer, though Ryan played a supporting, tragic role. The series doesn’t shock us with a “twist” — it’s more interested in how and why a boy becomes capable of such violence. Did the show leave you feeling unsettled? What’s your take on how influence and identity play a role in real youth violence?