| For 16 years, police in Germany hunted a female serial killer whose DNA was identified at 40 crime scenes, including six murders. Exasperated, investigators dubbed her “the phantom of Heilbronn,” after the town in which she allegedly killed a policewoman. A state prosecutor on her trail said he “just couldn’t believe that the same woman could be capable” of all the crimes to which she’d been linked. Well, it turns out she wasn’t. Police officials this week revealed the source of the DNA they’ve been chasing all over Europe. It came from the cotton swabs used to collect DNA evidence at each of the phantom-killer crime scenes. The swabs had probably been contaminated by a woman who works in the factory where the swabs were produced. (HT: Deborah Kenyon) [%comments]
The Phantom of Heilbronn Unmasked
TAGS: crime
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I bet the company who provides the swabs won’t be getting any new business from German police anytime soon…
MAJOR setback.
If contamination is more likely to happen in batches of swabs, as opposed to one-offs, then taking a clue from medical science might help lower the odds of false samples. Do at least blind, if not double-blind sampling. You get two swabs, one you swipe it (maybe give it to another officer to seal), the other you open and seal back up (maybe give to the other officer to seal so its close to double-blind). Tag both, test both. If both turn up DNA of any kind, you know you can’t rely on either. You would only use as evidence in your case the DNA print of a pair sample where only one of the swabs had DNA.
Man goes to the doctor and says, “Doctor, what’s happening to me? Wherever I touch myself, it hurts!”
“Sir,” replies the doctor, “your finger’s broken.”
The fault actually lies with the police since the swabs in question were not supposed to be used for collecting DNA samples. Swabs for DNA collection are much more expensive than the ones used which suggests it was a cost cutting measure.
AFAIK normal procedure is to also send unexposed swabs to the lab doing the analysis. It’s strange this didn’t lead to earlier discovery.
One also has to question the intelligence of the investigators involved. When the policewoman was killed over a year ago and the story about the phatom hit the news for the first time it was immediately obvious that this is a contamination issue. Who seriously thinks it probable that the same women is involved in 37 cases all over europe and as diverse as breaking into garden houses, killing a cop and leaving her DNA traces on fired bullets and in a car used by a secret service operation?
The company is now claiming that the swabs were never declared fit for collecting DNA material with, since they were only sterilized to prevent infections, not to a degree that would completely destroy DNA material.
The police claims they were never told so.
This story line will probably show up on a Law & Order episode in about two months.
You’d think the police might want to verify the sterility of their tools. I would certainly expect the same from my doctor.