Tuesday, 9 June 2009

Hunting Phantoms

Last year German police was hunting a phantom, a woman that was supposed to have committed a long list of crimes, among them several murders, burglaries etc. Her DNA had been recovered from crime scenes from various places in Germany. After several months it transpired that the problem lay in the cotton buds that had been used to recover the DNA samples from the crime scenes. Although the cotton were specified as ultra pure and suitable for sampling DNA, cotton buds from several batches had been contaminated. One worker had obviously touched them during the manufacturing process and it was her DNA that had apparently been recovered from the different crime scenes. Another aspect that became obvious was that of course no real DNA had been sampled at all at the crime scenes as the DNA had been on the cotton buds right from the beginning. Therefore police had to rethink their sample taking techniques. Just rubbing your cotton buds on surfaces at the crime scene in the hope to catch some DNA is simply not good enough. Sampling trace evidence is a tricky business.

But it does not need trace analysis to hunt a phantom as the Irish police found out these days. Irish police was trying to track down a Polish motorist who had committed dozens of speeding and parking offences across Ireland while continuing to elude the courts. Under the name of Prawo Jazdy he had left a trail of multiple identities and vehicles in the Police's database. Then someone had the good idea of taking a closer look at "Prawo Jazdy". Far from being a name it turned out to be Polish for driving licence"....

1 comment:

  1. pre-contaminated sticks will always be a problem. We had issues with chemical contamination in a process. It turned out that the maker of the gloves had used baby power, then try to fixed the batch by washing it. It didn't work. The real fix is to run tests on each batch coming into the lab. If you get DNA from a clean swab return for a refund.