A Series of Killings Was Pinned on a Mystery Woman. Then the Case Took a Shocking, 'Phantom' Turn

How many years does it take to track down a killer who doesn’t really exist?

Two years, police in Germany found out in 2009, after it was revealed that one of the country’s most untraceable killers was, in fact, non-existent.

The case of the “Phantom of Heilbronn” turned out to be one of history’s most embarrassing. German law enforcement, having spent two years and well over 16,000 overtime hours investigating dozens and dozens of crimes they thought to be connected, found out that the “culprit” they had in mind was a figment of faulty DNA samples.

Time magazine reported that police across the country were convinced a female serial killer was in their midst for more than 16 years, with DNA evidence tying the mysterious suspect — dubbed the “Phantom of Heilbronn” — all the way back to a 1993 murder. But in 2009, a discrepancy during a DNA test began to shine light on the real culprit: an innocent factory worker in Austria, whose DNA happened to have wound up on swabs used by German investigators in every instance.

Fifteen years later, PEOPLE is taking a look at how the bizarre case unfolded.

The ‘Phantom of Heilbronn’

News of the “Phantom of Heilbronn” first spread across Germany – and throughout Europe – in 2007, when a 22-year-old police officer in the southern city of Heilbronn was murdered and DNA recovered at the scene matched a number of other crimes throughout Germany. 

Police traced the suspect’s DNA to 40 crime scenes throughout the country, as well as Austria, leading the public to dub her the “Phantom of Heilbronn” and “The Woman Without a Face,” according to the BBC.

In what may have been a red flag in retrospect, police tied the “Phantom” to a wide range of crimes: six murders and a multitude of thefts and break-ins, ranging from schools to car dealerships. According to Time, the supposed “Phantom” killer had also collaborated with accomplices from Serbia, Slovakia, Albania, and Romania, among other people. In every instance, people already behind bars for those crimes denied they had a collaborator who matched the profile of the “Phantom.”

Years of Searching, But No Results

Time reported that German police’s two-year search for the “Phantom” stretched to Austria and France. According to the BBC, police also offered a €300,000 reward for information leading to her arrest.

In 2009, police finally began to suspect something far more embarrassing had been taking place, according to The Times of London. Investigators testing DNA on the charred remains of a male asylum-seeker in France found that, surprisingly, the DNA matched that of the “Phantom of Heilbronn.”

“Obviously that was impossible, as the asylum-seeker was a man and the Phantom’s DNA belonged to a woman,” Ernst Meiners, a spokesman for the public prosecutor’s office in Saarbrücken, Germany, told The Times. “That aroused suspicions that the materials were contaminated.”

What Really Happened

Now, with suspicions turned solely on themselves, police began to investigate what they could be doing wrong when taking DNA samples.

According to the BBC, police soon realized that every DNA sample for the crimes in question dating back to 1993 matched a female factory worker in Bavaria. The factory where she worked produced cotton swabs that had been used for DNA collection.

A spokesperson for the police union in Baden-Württemberg called it “a very embarrassing story,” according to The Times.

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The factory behind the cotton swabs clarified that their products were for medical purposes — and not qualified for DNA testing, according to the publication, which also reported that although cotton swabs are disinfected before leaving the factory, disinfecting them does not remove DNA.

“DNA analysis is a perfect tool for identifying traces,” Stefan König from the Berlin Association of Lawyers concluded in an interview with Time in 2009. “What we need to avoid is the assumption that the producer of the traces is automatically the culprit.”