Dutch Cold Case Murder Solved After 8000 People Gave Their DNA 513
sciencewatcher writes "A 1999 cold case rape and murder in The Netherlands has been solved. Dutch police asked 8000+ men living within 5 kilometers of the crime scene to volunteer their DNA so that the murderer could be traced through (close or distant) family members sharing part of this DNA. As it turned out, the man now in custody turned in his own DNA, resulting in a 100% match. The request of the police was discussed here on Slashdot in September. The percentage of people participating was closing in on 90%; in the midsize town of the victim it was 96%."
Re:Privacy issue: DNA dragnets (Score:5, Informative)
Assuming you're referring to this article in particular, let me define the most important word in the summary.
volunteer/välnti()r/
Noun: A person who freely offers to take part in an enterprise or undertake a task.
Verb: Freely offer to do something
If you're referring to some possible future event that may or may not happen and is vaguely related to this, then please disregard.
Re:Solved? Not quite. (Score:5, Informative)
I know this is breaking the rules, but I've read TFA. The DNA sample was found on a lighter in the girl's bag next to her body.
Not just on the lighter
From TFA: ...cigarette lighter found in Vaatstra's bag which contains dna traces that match the traces found on the schoolgirl's body. "
"
Re:Sounds improbable (Score:5, Informative)
The DNA matched DNA found on a cigarette lighter found in her schoolbag - not DNA from the rape itself apparently.
The DNA on the lighter matched DNA from the rape itself. The importance of the lighter is that it was sold during the time of the rape in that narrow area - placing the rapist as a resident of that area at the time, and giving high probability that a scan of all the residents would strongly indicate who the attacker was. If the lighter wasn't found, this search couldn't be justified as the rapist could come from anywhere.
Re:Sounds improbable (Score:5, Informative)
Re:Solved? (Score:3, Informative)
Everybody in the Dutch talks as if the man is convicted already.
Ok .. this is so untrue...
This is the news article from the major Dutch online newspaper. Put it through Google translate if you don't trust my translations:
nu.nl [www.nu.nl]
AMSTERDAM - A suspect has been apprehended in the 'Marianne Vaatstra' case. The Procesution Councel (PC) confirmed it this monday morning.
...
The Justice dept. will not reveal any details for now. The PC and Frysian police force will hold a press conference 18:00 CET in Drachten.
...
The Dutch Forensics Institution (NFI) is currently performing a minute double-check of the identity of the suspect.
"For both PC and police force it's of major concern we only submit an official statement to the press when it's certain the identity of the suspect is confirmed without question by the NFI."
...
Moreover [the spokeswoman of the PC] emphasizes DNA will 'never be enough', "there always will need to be more evidence".
Re:Sounds improbable (Score:4, Informative)
According to TFA, the lighter had DNA that matched trace collected from the girl's body. The lighter is significant because it was being sold in the area at the time of the crime, meaning that the murderer was likely local and not from abroad. This was what motivated the mass DNA testing - it was no longer a shot in the dark.
Re:Sounds improbable (Score:5, Informative)
No, that's patently incorrect. The article (which I read, shame on me) makes it clear that the DNA on the cigarette lighter matches DNA present on the body of the victim:
The decision to launch the dna appeal came after De Vries in May broadcast information about a Playboy cigarette lighter found in Vaatstra's bag which contains dna traces that match the traces found on the schoolgirl's body.
More or less, they found DNA on her body, but had no immediate reason to suspect it was from someone nearby. When they found the same DNA on the cigarette lighter and were able to determine that the cigarette lighter was on sale in that area around the date that the rape/murder occurred, they thought they had reason to suspect a local individual was involved. That's what led to the DNA dragnet.
I do agree that police need to be careful with DNA evidence and not use it as proof of guilt where it implies no such thing, but that does not seem to be the case here.
Re:Sounds improbable (Score:4, Informative)
Re:Interesting (Score:2, Informative)
Except the birthday paradox doesn't apply. You aren't trying to figure out if a group exists where some set of two people have similar DNA. You instead have a fixed set of DNA that you are comparing to each and every other person in the group. Big difference.
Re:Interesting (Score:5, Informative)
Re:Interesting (Score:5, Informative)
No, no, no, no, no! In a room of about 20 people there is a 50/50 chance of having two people with the same birthday. This is absolutely different of you having the same birthday as someone else, which is about 5.5% chance.
-- Pete.
Re:Sounds improbable (Score:5, Informative)
A regular DNA test has about 1/10000 success rate, but I would think that one can run a more thorough test (for a cost) that is much more precise than that. DNA doesn't have that collision rate.
That's the theoretical rate based on calculating the genetics of the population; it assumes that you run the scan perfectly. In fact labs make mistakes and cross contamination happens. This is something where the basic principle of science; actually do the experiment and see; must override the theory.
When people actually the lab error rate for genetic tests they get numbers like 1.7 in 1000 [bmj.com] measured false positive rate. If you know a set of results where independent blind testing of the Dutch police DNA system has returned better results, please point to your peer reviewed study which shows so. I believe that most police labs aren't even subject to blind testing, so an even higher error rate should be expected.
Re:Interesting (Score:4, Informative)
You should find it scary. The odds of a false positive are probably much higher.
The DNA database in the US has found matches between a black man and a white man if you point it at itself. They only look at about 12 spots and sometimes use just 9 to identify someone.
"903 pairs of profiles matching at nine or more loci in a database of about 220,000. ...State officials obtained a court order to prevent distribution of the results."
http://news.lawreader.com/2008/07/22/dna-match-between-two-men-raises-question-about-validity-of-dna-tests%E2%80%A6fbi-seeks-to-block-inquiry/ [lawreader.com]
http://www.deathpenaltyinfo.org/accuracy-dna-matches-definitively-identify-suspects-questioned [deathpenaltyinfo.org]
Re:Interesting (Score:5, Informative)
The devil is in the details. I don't say you HAVE to trust your government, just that it's sorry IF you CAN'T trust the government. But then, maybe this is all because of cultural differences and we'll never agree.
Now, in what world would you live if you actually COULD trust the government to do good things and they would? Or if you knew that when they did wrong it could be amended just by a proper re-vote instead of having to implement drastic measures like carving the right to bear arms into a constitution which will fly out of the window anyway if a government really wants to implement evil... and in the mean time will inflict all kinds of harm to society. (Excuse me if I'm uninformed but I regularly read about all kinds of nasties happening over the pond, like public place mass murders, children having gun accidents, increased rates of crimes with lethal consequences etc. Here those things are... drastically less frequent.) Of course, it's your nation.. your peoples decisions. Not wanting to lecture here but please do allow me to find things odd, as you do about us.
Think about it.
Now, mod me into oblivion if you're a true patriot. I'm nothing of the sort. But I am someone willing to trust until someone shatters it... within common sense of course. I'm not that much willing to hand over advance fees to Nigerian princes.
Re:Exactly (Score:4, Informative)