Man, remember when we all first hit play on that first episode? We thought it was a straightforward revenge thriller. Alex Guzman gets out of prison, hacks some cameras, and makes the Lazcano family’s life a living hell because they framed him for his sister’s death. Simple, right? Wrong. By the time we actually got to the end of Who Killed Sara Netflix fans were basically losing their minds trying to track the timeline. It wasn't just a murder mystery; it was a deep dive into psychological trauma, unethical medical experiments, and a web of lies so thick you'd need a chainsaw to get through it.
Honestly, the showrunners kept us guessing for three seasons because they kept changing the "who" in the equation. First, we thought it was Mariana. Then maybe César. Then we were convinced it was Marifer. But the reality of what happened to Sara Guzman is way darker than a simple parachute "accident."
The Parachute Was Just the Beginning
Let's get the facts straight about the incident at the lake. For the longest time, the show led us to believe that the cut straps on the parachute were the definitive cause of death. We watched Marifer, driven by a mix of resentment and family secrets, slice those straps. Sara falls. She hits the water. We see her in the hospital.
But here is where the show gets really twisty.
While Marifer thought she killed Sara, she actually didn't. The fall didn't end her life. It was just the catalyst that allowed Dr. Reinaldo Filho to step in and snatch her away. If you're looking for the real answer to Who Killed Sara, you have to look past the Lazcano family and toward the Medusa Project. This is where the show shifts from a soapy melodrama into something much more sinister.
Who Really Killed Sara? (Spoiler: It’s Not Who You Think)
The final season pulls back the curtain on Reinaldo. He's Nicandro’s father, and he’s basically a mad scientist obsessed with "curing" homosexuality and schizophrenia. He viewed Sara as the perfect specimen because of her genetic predisposition to mental health struggles, inherited from her biological father, Abel.
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Sara didn't die at the hospital after the fall.
Reinaldo faked her death. He had her moved to a secret facility where he performed horrific experiments on her for months. It’s heavy stuff. We find out that Sara eventually gave birth to her daughter, Jeanette, while in captivity. But the psychological and physical torture became too much.
The truth is that Sara killed herself.
She took her own life to escape Reinaldo's reach and to ensure he couldn't use her anymore. It’s a tragic, gut-wrenching realization for Alex. He spent eighteen years in prison fueling his soul with the fire of revenge against the Lazcanos, only to find out the monster was a man he barely knew. Reinaldo is the one who drove her to it. He is the murderer in every sense that matters, even if he didn't pull a trigger or cut a rope.
The Medusa Project and the Schizophrenia Subplot
One thing the show caught a lot of flak for—and honestly, rightfully so—was its portrayal of mental health. Sara’s diagnosis of schizophrenia was used as a plot device to make her an "unreliable" character. It added layers of complexity, but it also felt a bit tropes-heavy at times.
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Nicandro’s involvement always felt shady. In season two, we see him talking to the doctor, hinting that they "let the Lazcanos think they did it." That was our first real clue that the mystery went deeper than a rich family protecting their reputation. Reinaldo’s facility was the "Medusa" center, and his goal was a twisted version of conversion therapy. He believed he could "fix" people through trauma and brain surgery.
- Sara was the "Patient Zero" for his theories.
- She was kept in a sterile, white room.
- She was monitored 24/7.
- Even her "friend" Nicandro was essentially her handler.
It makes you look back at the early episodes differently. Every time Sara seemed "erratic," was she actually reacting to the gaslighting and manipulation of the people around her? Probably.
Why the Lazcanos Were Still the Villains
Even though they didn't technically kill her, the Lazcano family is far from innocent. César is a monster. Mariana is a cold-blooded manipulator. They were perfectly willing to let Alex rot in jail for a crime he didn't commit because it served their interests.
The beauty of Who Killed Sara on Netflix is how it explores the concept of guilt. Marifer died believing she was a murderer. Alex lived his life as a convicted murderer. César lived as a man who would have been a murderer if he had to be. In the end, the show argues that the "killer" isn't just one person with a knife; it's a system of toxic masculinity, wealth, and ego that crushes anyone in its way.
Breaking Down the Final Episode
In the series finale, Alex finally finds the facility. It’s a bloodbath. He’s done playing games. The confrontation with Reinaldo is intense because it’s not about a mystery anymore; it’s about justice for a woman who was treated like a lab rat.
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Alex kills Reinaldo using an experimental chair—the same kind of device Reinaldo used on his patients. It’s poetic, sure, but it’s also incredibly dark. When Alex finds Sara’s grave, the one with the actual date of death that happened long after the parachute accident, the weight of the eighteen lost years finally hits him. He was chasing a ghost, and the ghost was created by a man's god complex.
What Most People Get Wrong About the Ending
A lot of viewers were confused about whether Sara was actually dead. There were theories floating around Reddit for years that she might still be alive, hiding out somewhere. But no, the show confirms her death. The tragedy is that she survived the fall only to be broken by the medical system.
Another misconception is that Marifer's actions didn't matter. They mattered a lot. If Marifer hadn't cut the straps, Sara wouldn't have been injured, she wouldn't have gone to that specific hospital, and Reinaldo wouldn't have had the opportunity to "claim" her. Marifer provided the opportunity, but Reinaldo provided the motive and the final blow.
Actionable Insights for Your Next Binge-Watch
If you’re planning on rewatching Who Killed Sara or diving into similar Mexican thrillers like The Surrogacy or Dark Desire, keep these points in mind to catch the clues earlier:
- Watch the background characters. In the first season, Nicandro seems like a side character, but his presence is the thread that leads to the real killer.
- Follow the money, not the blood. Most of the characters are motivated by protecting their inheritance or their status. Only Alex is motivated by the truth.
- Pay attention to the dates. The timeline of the show is notoriously messy. If you look at the dates on the hospital records and the tombstone Alex finds later, the math only works if you accept the secret facility plotline.
- Analyze the "diary" entries. Sara’s journals were the window into her mind, but they were also a roadmap of her fears. She knew someone was coming for her; she just didn't know which monster it would be.
The show is a wild ride. It’s messy, it’s dramatic, and sometimes it’s downright unbelievable. But at its core, it’s a story about a brother’s love and the horrifying lengths some people will go to for "science" and power.
Now that you know the truth behind the Medusa Project, the mystery is solved. But the impact of that betrayal stays with you long after the credits roll on the final season.
Final Verdict on the Mystery
- The Saboteur: Marifer (cut the parachute).
- The Puppeteer: Reinaldo (faked her death and tortured her).
- The Ultimate Cause: Suicide (to escape her captor).
- The Scapegoat: Alex Guzman (spent 18 years in prison).
If you’re looking for more twisty mysteries, your next step should be checking out Control Z or The Mess You Leave Behind. Both offer that same high-stakes, "everyone is lying" vibe that made this show a global hit. Just don't expect the answers to be any less complicated.