The Heilbronn DNA Mixup
I wish I’d written earlier about this to appear really smart. Anyway, here’s the backstory: DNA traces of an unknown eastern-European woman had been found at almost
The Culprit
17 crime scenes, including two murders (including a 22 year old police officer) but also car jackings, unprofessional break-ins and on a bullet fired in a marital dispute. The crimes where spread around a large area including south-west Germany, France and Switzerland.
It now turns out that the several-hundred-men task force might have really been chasing a phantom. Alarmed by the apparent randomness of the crimes, involving both highly professional work and seemingly amateur break-ins, they started checking for contaminations in the labwork. The likeliest suspect now are the cotton swabs used to collect evidence at the crime scene. All the swabs used in the forensics works were sourced from the same supplier, a company in northern Germany that employs several eastern-European women that would fit the profile. Even more inciminating, the state of Bavaria lies right in the center of the crimes’ locations, without ever finding matching DNA in crimes on its territory. Guess what: they get their cotton swabs from a different supplier.
While the suspicion had already been growing in the last few months, the smoking gun apparently was a case where they tried to match a burned (male) corpse to DNA collected from fingerprint samples an asylum-seeker had given a few months earlier. The first test showed a match between those fingerprints and the Phantom’s DNA while a second test did not.
By the way: contaminated cotton swabs aren”t as trivial to avoid as one might think. It’s relatively easy to sterilize cotton to prevent infections. Forensics however require a complete destruction or removal of any DNA contamination, which is apparently a lot harder.
That’s quite dumbfounding. Couldn’t they figure that out before? Why do they use cotton swabs in the first place? That doesn’t seem appropriate. I would have thought forensic science was a lot more accurate and reliable than that. A huge task force being misled for 15 years by their own cotton swabs, how many other investigations did they screw up?
“I would have thought forensic science was a lot more accurate and reliable than that.” And there is your first mistake. You are in good company though, apparently courts have a term the “CSI effect”, where juries think that they can convict easily on the forensic evidence presented before them. It’s obviously not as easy as what is shown on CSI.
I’m glad I don’t work in a cotton swab factory. It would be a pain to be a suspect in so many crimes.
On the other hand, if you can prove you weren’t in 10 very different places at once, then your DNA at the genuine crime scene could also be discounted.
Yes – this is shockingly bad science costing the taxpayers millions. The tests should have included a Negative Control. This is science-talk for testing a “pure” untouched swab. This would have revealed the problem at the beginning. What else are these labs doing wrong?
In their defence, they did do control tests on quite a few swabs apparently, but only a minor percentage might have been contaminated and none of those were tested.
I’ve also observed the “CSI effect” in the opposite where juries will acquit despite solid, non-forensic evidence because they demand the (incredibly expensive) forensic research they see so often on TV.
I hope that there arn’t a few innocent Eastern European women in jail because of this. This was because of unsolved crimes. The bigger porblem would be the falsely solved crimes!!
You know, that incredibly expensive forensic evidence is important. Do you have any idea the percentage of wrongfully convicted people there are? The number of men that are being set free nowadays for rapes they didn’t commit based on DNA evidence is staggering. Men that’ve been in jail for 10, 20, 30+ years. Because they didn’t have that forensic evidence back then, but they had very solid “traditional” evidence.
It’s Carmen Sandiego!
@Aaron
Meaning what? Always reliable eyewitness testimony?
I wonder how many trials have to be retried now?
None, probably. DNA-tests are fundamentally sound. The DNA was actually there. It’s well known that a crime scene can be contaminated, by DNA that was there before the crime for example. In some countries it’s not even possible to convict someone by DNA evidence alone.
All in all, DNA is the greatest progress in forensics since the fingerprint, reducing both false positives as well as false negatives. Just think of the hundreds of sometimes decades-old cases that were either solved or where a wrongfully convicted was exculpated by DNA evidence.
It’s good to see the “Keystone Cops” are alive and well in Europe!
Seems like forensics needs somrthing like a lights test which is used to check that all the alarm lights are working correctly.
@CoolKev
thank you for that observation now i wish to add one of my own. looking back on the steven kisko, his jailing, release and death directly related to his experiences at the hands of prisoners and guards alike i cannot avoid wondering how the totally inept police imspectors who chose to vilify a nearly mentally incompetent in favour of a proven child killer are squirming in thier comfortably paddedd officers chairs. ewqually amusing if hat is a term applicable to thier despicable action would be a opportunity to be the fly on the wall of the counties crown prosecutors, memebrs of the judiciary who tried the case and the public who se lies ruined the family of a truly innocent man.
it is however most unlikely that any of the above will ever even flinch at the prospect of thier ignorance of being and remaining ignorant of the true conditin of the evidence produced in that and other prior or subsequent trials for the alleged exposures and murder should be disputed for what it was, totally bogus.
last item this will really put a spin on the genetics abd geneology fields won’t it?
ne variatuer
This problem is not surprising. A similar problem involving the tubes used during the testing process occurred in the US several years back. Perhaps scarier is the fact that many labs in the US test samples from the suspect, victim, and crime scene at the same time, in the same place. So if a contamination occurs between the suspect’s sample and the evidence then the suspect pretty much own the crime whether they were involved or not. The classic undetectable false positive!
Zeek
I kind of expected someone would mention CSI sooner or later. But I have never even watched it! I only heard of it. What made me think it’s “accurate and reliable” is that in a lot of real-life trials, it seems to be used as the most irrefutable proof of all, the one that tells who the guilty party is as clearly as he had been caught on camera.