"The Breakthrough" True Story: Inside the 2004 Double-Murder That Inspired the Netflix Series (and Why the Case Went Unsolved for 16 Years!)

01/10/2025 06:50 PM

The Netflix series is inspired by a real-life double murder that occurred in Sweden in 2004

The Breakthrough follows a double murder that took 16 years to solve — much like a real-life incident that occurred in Sweden in 2004.

Based on the 2021 novel of the same name, the Netflix series recounts the chilling story of a long-unsolved case involving the fatal stabbings of a young boy and a middle-aged woman. Sixteen years later, police officers teamed up with a genealogist who use advanced technology to identify the killer. Although it is a fictional drama series, it is inspired by real-life events that were explored in the novel.

In November 2022, scriptwriter Oskar Söderlund told Netflix that upon reading The Breakthrough, hewas "struck by the fact that there was such strong human destinies behind this massive murder investigation."

"Police officers who refuse to give up, relatives who wanted answers and last but not least the genealogist who finally came up with the solution," he said. "It is a terrible trauma that has affected the people and the city of Linköping and I want to respectfully tell about the attempts to move on from such trauma."

So, what is the true story behind The Breakthrough? Here's everything to know about the real double murders that struck Sweden in 2004 — and why it took 16 years to find the killer.

Is The Breakthrough a true story?

The Breakthrough begins with a young boy on his way to school when he is stabbed by an unidentified man. A middle-aged woman intervenes, and as a result, he stabs her, too.

A bystander reports the crime to the police, but despite the clues she brings, the case remains unsolved. Throughout the four-episode series, officers and genealogists work over the course of 16 years to uncover the truth behind the brutal attack and identify the killer. In the end, it's the DNA of a journalist trying to write about the technology's role in the case that leads investigators to a man named David Nilsson.

Although the Netflix show is considered a fictional drama series, it is based on the nonfiction book written by journalist Anna Bodin and genealogist Peter Sjölund in 2021. In a November 2022 statement to Netflix, the authors said they were excited that a story based on their "extensive work" would be told by FLX and Netflix.

"This is the first criminal case in Europe that has been solved with genetic genealogy, and it is a case that has touched both of us, the city of Linköping and Sweden deeply," the statement continued.

What happened in the real-life case of The Breakthrough?

Much like the series, a double homicide occurred in 2004 when an 8-year-old boy and 56-year-old woman were fatally stabbed by an unknown attacker, per The Local Sweden.

According to the outlet, the boy had been on his way to school, while the woman was headed to work. Police were called to the scene early in the morning, where they first discovered the woman had been stabbed in the stomach. She was transported to a local hospital and died during surgery. Meanwhile, the boy was found at the scene lying nearby with a cut throat and was pronounced dead upon arriving at the hospital.

Witnesses described the killer as being in his twenties, dressed in a beige knee-length jacket and blue or black woolen hat, and told police that he "did not run but strolled away from the murder scene," per The Local Sweden.

As illustrated in The Breakthrough, the murder weapon was believed to be a butterfly knife.

According to The Guardian, the weapon was found at the scene alongside the suspect's DNA and a bloody cap. But despite the clues, the case sat unsolved for years as investigators struggled to identify the killer.

How was the murder in The Breakthrough solved?

According to The Guardian, new legislation was passed in January 2019 that enabled police to search for DNA matches on commercial genealogy websites. This development led law enforcement to collaborate with genealogists to reopen and continue investigating the cold case 16 years after the tragic event.

The genealogists interviewed and tested the DNA of thousands of people. After creating family trees, the results led investigators to a pair of brothers — as they did in the Netflix series — before they ultimately found their match, per a September 2020 report from The Nomad Today.

In June 2020, police identified a killer and released a statement that said they "received a match almost immediately," per The Guardian.

They added that "his DNA was taken and matched 100%," as shown in the Netflix series.

Who was the real-life killer from The Breakthrough?

After matching his DNA on a popular genealogy website, Daniel Nyqvist was identified as the killer. According to The Guardian, Nyqvist — who was 21 at the time of the attack — admitted to police that he had obsessive thoughts about killing and chose the victims randomly.

Medical experts concluded he had suffered from a psychiatric disorder, which became his lawyer's defense for rejecting the charge of premeditated murder, per the outlet.

Additionally, The Guardian reported that the killer said during the police interrogation that he never expected he would go unscathed for so many years.

"I remember that I didn't brush my teeth because I was just going to die or get caught that day," he said. "But I had to do it. I did it mostly on automatic."

Nyqvist had been unemployed and living at his parent's home during the murders and continued to live a quiet life near Linköping following the attack, per The Guardian.

Who were the real-life victims from The Breakthrough?

The young boy killed by Nyqvist was identified as Mohamad Ammouri. According to The Local Sweden, it was a normal morning for Ammouri, who was on his way to school when he was killed.

"Mohamad overslept and got up at about quarter past seven. He was worried about being late for school," Ammouri's brother Ali told the outlet. "My mum prepared a simple breakfast which he ate before he took his schoolbag and ran off."

Soon after he headed to school, Ammouri's sister Iman followed him, only to be met by disturbance in the streets and the image of a body lying in the road — the same way the scene unfolded in the Netflix series.

However, police prevented anybody from getting close enough to identify the body. Ammouri's school then called his family to ask why he hadn't arrived, per the outlet, which led them to find out the tragic news about their son.

"Just after nine we found out that our son had been killed," Ammouri's father told The Local Sweden. "He was radiantly happy and loved to joke with people. Why would anyone want to kill him? We have no enemies in the whole of Sweden."

The 56-year-old woman was identified as Anna-Lena Svensson, who worked for an educational company and was on her way to work when she was killed, per the outlet. She and her husband had a 28-year-old daughter.

According to The Local Sweden, the victims did not know each other, and police did not believe there was any connection between them and the killer.

Where is The Breakthrough killerDaniel Nyqvist now?

Sixteen years after the attack, Nyqvist confessed to the crime and was convicted of murder in October 2020, per The Local Sweden. According to the outlet, he was sentenced to psychiatric care after being found to have "committed the acts under the influence of a severe psychological disorder."

Nyqvist was also required to pay damages to the young boy's family, while the woman's relatives did not request anything, according to Swedish outlet SVT NYheter. Following his conviction, Nyqvist's lawyers said he would not request an appeal to the verdict, per a translated report from Swedish outlet Corren.

According to Nyheter24, as of October 2024, Nyqvist — who goes by a different name now — remains in forensic psychiatric care at Regional Clinic in Vadstena, Sweden, per a request from the Administrative Court in Linköping.

Court records reviewed by the outlet reveal that his healthcare has been running smoothly, with no psychiatric symptoms observed in the past six months. The documents also noted that he recently began taking medication as a precaution and feels that his sleep has improved.