by Kieran Healy on May 14, 2004

My post “about voting networks in the Eurovision”: led to a followup from “Danyel Fisher”:, a grad student at Irvine who studies social networks. His “weblog”: is has lots of interesting stuff, including a better-informed version of a post I’ve been meaning to write for a while about “fingerprint databases”: When the U.S. announced that it was going to fingerprint visitors entering the country, I began to wonder when the vast size of these databases was going to run up against the problem of false positives. Although we think of fingerprints as unique, the matching process is prone to error (like everything) and, for a large enough scale, your prints may be essentially identical to someone else’s. Daniel’s post links to a story where exactly this happened, in the case of the Spanish investigation into the train bombings. A perfect match turned up in Portland, Oregon.

Danyel links to a paper “On the Individuality of Fingerprints”: (pdf). I also know of — but haven’t read — Simon Cole’s “Suspect Identities”:, a study of the emergence and institutionalization of standards for fingerprinting.



John Quiggin 05.14.04 at 9:55 am

I’ve been worried by this same case, but didn’t chase down the info on matching odds.

The other issue is the material witness rule under which it’s apparently possible to be detained indefinitely – not as terrifying a status as “enemy combatant”, but apparently firmly grounded in US law. Can anyone advise on when habeus corpus can be brought to bear in cases like this.


mm 05.14.04 at 1:36 pm

No, but I can tell you that the word is spelled habeas, being the (jussive) subjunctive form of habeo.


Zizka 05.14.04 at 2:45 pm

The individual being held is an American convert to Islam who served as the lawyer for an American Muslim who was later convicted of involvement in terrorism. The case he was involved in was prior to and unrelated to the terrorism case. The lawyer was a military veteran so his fingerprints were on file. The Spanish police are uncertain about the fingerprint match and I believe that the US people just set their parameters loosely to get the most matches possible with the maximal database of people they already had their eyes on for some reason. There’s no evidence that the man was ever in Spain, and pretty good evidence that he wasn’t.

Civil libertarians here in Portland are on the defensive because in the previous local terorism case all the defendant eventually pled guilty, including one whose guilt had initially seemed unlikely. (Of course, the threat of Guantanamo and/ or execution could extract guilty pleas from people, but at this point it seems unlikely that that’s what happened — the defendants had good representation).

I believe that some aspects of the material witness law are new, either from the PATRIOT act or from RICO statutes. The anti-drug and anti-militia laws of the Clinton era made Ashcroft’s work much easier. There’s been a precipitous decline in civil liberties over the last 10-20 years.

One of the witnesses in the Clinton fiasco, Susan McDougal, still claims that she was pressured to provide perjured testimony against Clinton, and served over a year in jail for refusing to testify. The material witness law certainly would be useful for a prosecutor in this kind of situation. There is substantial sentiment in the American judiciary to give police a free hand.

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