Tainted swabs lead police on wild goose chase for 'serial killer'

German police spent two years hunting "the Phantom of Heilbronn", only to find they had been fooled by a tainted supply of cotton swabs.

BERLIN // It is one of the biggest and most embarrassing bungles in the history of German crime fighting. Police spent two years hunting "the Phantom of Heilbronn", believed to be a female serial killer who had left her DNA at 40 crime scenes, only to find they had been fooled by a tainted supply of cotton swabs.

Police and state prosecutors across southern Germany as well as in Austria and France hunted the mysterious woman who had committed a bizarre variety of crimes ranging from cold-blooded murder to burglary, petty theft and vandalism. Police admitted this week they had been led on a wild goose chase as a result of faulty cotton swabs used in collecting DNA from various crimes scenes. The DNA was traced on Friday to a less than meticulous female packer at a medical products company in Bavaria.

Bild, Germany's best-selling daily newspaper, described the fiasco as "the most embarrassing police error of all time" and asked: "Have the police got cotton wool in their heads?" Police have been quick to dismiss concern that the case has damaged a key tool of modern crime-fighting - extracting DNA evidence from hair, skin or blood left at crime scenes. German police authorities pledged to co-operate to develop common standards for collecting forensic evidence in the future. "The weak point now identified will lead to decisive improvement in gathering evidence," Klaus Hiller, the president of the regional criminal police force in the state of Baden-Württemberg, told a news conference. That may not be enough to silence criticism given the thousands of hours of police time wasted in probes and the prospect that dozens of crimes will have to be re-investigated. To make matters worse, it emerged this week that German police ignored warnings from their Austrian colleagues that there might be something wrong with their forensic checks.

In addition, the medical products firm that supplied the swabs, Austrian-owned Greiner Bio-One, said they were never intended for use in DNA tests. "The swabs are exclusively suited to medical purposes," the firm's manager, Heinz Schmid, told a news conference. One police investigator said: "The things came in double packaging. We thought they were the Mercedes of cotton swabs." The mistake originated in April 2007, when a policewoman was shot dead in the southern town of Heilbronn. Police swabbing the crime scene found the DNA of a woman on the police car. It was matched to DNA found in two other unsolved murder cases - the strangulations of a woman in 1993 and an elderly German man in 2001, both in southern towns.

As their fruitless hunt for the murderer of their colleague grew more desperate, police started checking all new crime scenes, even burglaries, for the DNA in a bid to track her down. Fooled by their faulty swabs, police linked the DNA to 40 crimes, including a total of three killings and two attempted killings, and became convinced they were hunting a female mastermind with an eclectic taste in crime.

"Since April 2008, police had been saying the evidence wasn't plausible. Something didn't fit. They couldn't construct a psychological profile of the perpetrator," said Heribert Rech, the interior minister of Baden-Württemberg last week. The phantom's DNA started turning up everywhere - on a half-eaten biscuit in a vandalised garden shed, on a discarded drug syringe, on the bullet a man had fired at a relative in a domestic dispute and had got lodged in a living room wall. She also stole a guitar, according to police. An array of robberies and burglaries was attributed to her. Her DNA turned up in 16 cases of theft in Austria, too.

Police who voiced doubts because their experience and gut instinct told them the pattern of crimes did not fit were ignored. The DNA evidence was followed blindly even though witnesses to the various crimes never reported seeing a woman. So the police concluded she may look like a man, and was probably transsexual. Last Wednesday evening, Baden-Württemberg's police force officially admitted that the DNA traces were "no longer plausible" and that police had been looking at the possibility of a "foreign contamination" since February.

Austrian police said they had warned their German colleagues last year that something must be wrong because they had found the woman's DNA on the finger of a 21-year-old man beaten to death in a pub brawl in Linz last September. The assailants, all male, were apprehended and no woman had been seen in the vicinity. German police were finally swayed when they found the DNA on the file of an asylum-seeker they were trying to match to an unidentified corpse.

Unsurprisingly, Germany's Federal Criminal Police Agency BKA, which has DNA records on more than 620,000 people in its database, has called for a review of police forensic techniques to rule out future contamination. The case has raised serious doubts about the reliability of that database. A BKA spokesman said it would be "speculative" to comment on how many of the records might be tainted by faulty evidence- gathering equipment.

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