BERLIN German police are struggling to explain why they chased a phantom serial killer for 16 years after confusion over an innocent woman's DNA samples.
Police in the southern state of Baden-Wuerttemberg had searched since 1993 for a woman they believed had taken part in more than 40 crimes, from murders to muggings. Her DNA was found repeatedly at crime scenes in Germany, France and Austria.
But the DNA came from an unsuspecting woman working at a factory in southern Germany, where cotton swabs are produced for the police force, investigators said.
They suspect she may have sneezed on the swabs used to collect evidence and contaminated them. This reproduced the woman's DNA matches despite her having nothing to do with any of the crimes.
Police had promised a 300,000 euro ($400,000) reward to anyone who helped find the elusive killer, thought to be involved in six murder cases. They held a news conference on Tuesday to respond to widespread criticism of the mix-up.
"The cotton swabs were contaminated through human contact in the factory where they were produced," Horst Hauk, a spokesman for the investigators, told Reuters.
Bernd Meiners, a spokesman for local prosecutors, said police first suspected something was wrong when a dead man's body produced female DNA earlier this month.
"As a result, we examined the cotton swabs that we used for collecting DNA samples and how they were manufactured," he said.
(Writing by Franziska Scheven; editing by Farah Master)