In 1993, a 62-year-old woman was found dead in her house in the town of Idar-Oberstein, strangled by wire taken from a bouquet of flowers discovered near her body.
Nobody had any information on what might have happened to Lieselotte Schlenger. No witnesses, no suspects, no signs of suspicious activity (except for the fact that she'd been strangled to death with a piece of wire, of course). But on a bright teacup near Schlenger, the police found DNA, the only clue to surface at all.
The case went cold, given that the only lead was the DNA of an unknown woman, and there was no match. Yet.
Eight years later, on 21 March 2001, a 61-year-old man was found dead in his kitchen in Freiburg, Germany. Again, the victim had been strangled, and this time the woman's DNA was found on a kitchen drawer. Similar methods of killing and an exact match for DNA had the police believing they may just have found a serial killer.
Then, following that gap of eight years, her DNA started to show up everywhere.
Five months after the second murder scene, her DNA showed up on a discarded heroin syringe, after a 7-year-old had stepped on it in a playground in Gerolstein. A few weeks later it showed up on an abandoned cookie in a burgled caravan near Bad Kreuznach, like she'd deliberately spat out a Jammy Dodger as a calling card. It was found in a break-in in an office in Dietzenbach, in an abandoned stolen car in Heilbronn, and on two beer bottles and a glass of wine in a burgled bar in Karlsruhe, like she'd robbed the place but stuck around for a few cheeky pints.
In one particularly bizarre case, on 6 May 2005, a man shot his own brother with a 7.65-caliber pistol. Her DNA was found on one of the bullets.
Over the apparent crime spree, her DNA was sprayed across an impressive 40 crime scenes in Austria, southern Germany, and France, including robberies, armed robberies, and murders. Where it got really weird is that at these crime scenes, police found the DNA of others, presumed to be her accomplices – but it was never the same person twice, and nobody would talk.
The woman was thus far dubbed "the woman without a face", but took on the name "The Phantom of Heilbronn" following the death of a police officer in the city. 22-year-old officer Michèle Kiesewetter was in her patrol car having lunch with her colleague, when two people climbed into the back seat of the vehicle and shot both officers in the back, killing her and injuring her partner.
DNA from the "phantom" was found on the back seat, as well as the dashboard. Baffled, the police put up a €300,000 reward for any information about her whereabouts. Not an easy task when so little was known, and when some witnesses would describe the suspect as a woman, and others as a man.
In 2009, the case got a new lead, and was finally closed for good with an embarrassing realization: The most notorious serial killer in Germany's history – thought to be responsible for six murders – didn't exist.
Police in France had discovered the burned body of a man, believed to be from an asylum seeker who went missing in 2002. During his application, the man had submitted fingerprints, which the police used to try and confirm his identity. Only, once again, they found the DNA of the phantom.
"Obviously that was impossible, as the asylum seeker was a man and the Phantom's DNA belonged to a woman," a spokesperson for the Saarbrücken public prosecutor's office told Spiegel Online in 2009.
Sure enough, testing the DNA again found that the phantom's DNA was not there. The man's death led to an explanation of the case: there was no serial killer, and the DNA could be traced to a woman working in a packing center specializing in medical supplies. It was all down to DNA contamination.
The police, for 16 years, had been tracking a serial killer and putting up massive financial rewards, only to discover that they'd been tracing their own contaminated swabs, like Shaggy following his own footprints in Scooby Doo.