Tag Archives: fingerprints

Maryland v. King No. 3: Bertillonage as Precedent

There are lots of criticisms that one can make of the majority opinion in Maryland v. King — and even more that apply to the dissent — but, contrary to one commentator, I do not think that the Court’s reference to the use of anthropometrics as employed in the late 1800s and early 1900s for authenticating the identities of prisoners is particularly problematic. … Find more at http://for-sci-law-now.blogspot.com/2013/06/maryland-v-king-no-3-bertillonage-as.html.

The Oral Argument in Maryland v. King — Part V

It is time to sum up and read the tea leaves that are the transcript of the February 26th oral argument in Maryland v. King. Previous postings concerned these topics:

Part I

  • Whether taking DNA profiles of arrestees is distinguishable from acquiring them from the general population;

Part II

  • Whether deriving information from database trawls that could inform pretrial release decisions and conditions can constitute a special need for warrantless DNA acquisition now or in the future;

Part III

  • Whether DNA profiles are distinguishable from fingerprints on the theory that collecting fingerprints is not even a search;
  • Whether DNA samples are distinguishable from fingerprints because DNA samples contain more personal information;

Part IV

  • Whether Kyllo‘s analysis of thermal imaging of a home applies to DNA profiling;
  • Whether the Court’s precedents show it is unwilling to trust the government;
  • How Skinner, Greenwood, and Davis (4th Cir. 2012) affect the claim that a laboratory analysis limited to identifying features is a search in its own right.

At least some of the Justices appeared to be searching for a theory that would distinguish routine DNA collection and analysis before conviction (DNA-BC) for arrestees from the DNA-BC for everyone in the population. But why? � read more �

DNA versus Fingerprints

A recent edition of The Economist reported on the perceived “CSI Effect.” [1] The following paragraph raised some eyebrows:

In reality, scientists do not deal in certainty but in probabilities, and the way they calculate these probabilities is complex. For example, when testifying in court, a fingerprint expert may say that there is a 90% chance of obtaining a match if the defendant left the mark, and a one in several billion chance of a match if someone else left it. In general DNA provides information of a higher quality or “individualising potential” than other kinds of evidence, so that experts may be more confident of linking it to a specific individual. But DNA experts still deal in probabilities and not certainties. As a result of all this reality checking, trials are getting longer and more cases that might previously have resulted in quick convictions are now ending in acquittals.

I am skeptical of the claim that television shows have converted quick convictions into acquittals, but even if that is true, how is DNA is more “individualising” than fingerprints? Fingerprints of identical twins are distinguishable. DNA profiles, in their current form, are not. The latter fact has been a problem in some investigations and prosecutions. Police investigating a notorious jewel heist in Berlin found DNA “in a drop of sweat on a latex glove discarded next to a rope ladder.” [2] When “they ran the material through the German [DNA] database, . . . [t]he computer identified two 27-year-old identical twins . . . .” Id. A German court released them, explaining that “[f]rom the evidence we have, we can deduce that at least one of the brothers took part in the crime, but it has not been possible to determine which one.” Id. According to a Time Magazine story:

Identical twins share 99.99% of their genetic information, and the tiny differences are impossible to isolate because of their nature; they tend to be spontaneous mutations limited to certain organs or tissues. “Identifying those [differences] would amount to dissecting the suspects,” says Peter M. Schneider, a University of Cologne forensic expert. “Our hands are tied in a case like this,” says criminal-law expert Hans-Ullrich Paeffgen of Bonn University. “The law doesn’t allow us to detain someone indefinitely just because he is suspected of a crime. This may be different elsewhere. But I’d rather live in a country where someone guilty is not convicted for lack of conclusive evidence than in a place where innocent people are locked up.”

This isn’t the first time an identical twin has proved impossible to pin down. The genetic material can thwart paternity tests if both twins claim — or deny — fathering a child. In the U.S., a jury in a rape trial in Houston deadlocked in 2005 when the DNA recovered at the crime scene matched identical twins who had kidnapped their victim together. A year earlier in Boston, a suspected rapist blamed his identical twin when confronted with the matching DNA. Although he was already serving a sentence for a rape conviction, the jury could not agree on a verdict, and the judge declared a mistrial. Earlier this year, an identical twin suspected of drug-smuggling and sentenced to death in Malaysia was set free when the court could not prove beyond doubt whether he or his brother had committed the crime.

Thus, fingerprint examiners like to claim that their information is more individualizing. But this overlooks the issue of whether today’s subjective comparisons of latent prints to clear, complete ones taken under controlled conditions are any more precise than STR profiling. Latent print examiners declare a match when they have a large subjective probability that the latent print and the exemplar originated from the same finger. In the United States, at least, the usual testimony for a subjective match is that the items came from the same finger. Do examiners ever testify to the likelihoods of competing hypotheses, as illustrated by The Economist‘s statement “that there is a 90% chance of obtaining a match if the defendant left the mark, and a one in several billion chance of a match if someone else left it”? Lacking the data to support statements like these and being trained to give categorical opinions about the source of a latent print, fingeprrint examiners do not seem to testify in terms of likelihoods. However, research supporting likelihood-based testimony exists, and the time is ripe for a change.


1. The “CSI Effect”, Economist, Apr. 22, 2010, http://www.economist.com/science-technology/displaystory.cfm?story_id=15949089

2. Claudia Himmelreich, Despite DNA Evidence, Twins Charged in Heist Go Free, Time, Mar. 23, 2009, http://www.time.com/time/world/article/0,8599,1887111,00.html

Striking Out with GINA

An article in the New York Times refers to the problems the major leagues have encountered in verifying the ages of young baseball players from the Dominican Republican. It reports that there is talk of taking fingerprints from aspiring players at around age 10. It adds that

The disclosure that Major League Baseball is considering fingerprinting young prospects comes six months after The New York Times reported that investigators for the commissioner’s office were conducting genetic testing on some Dominican prospects and their parents to ensure that the players were not lying about their identities and ages.

The practice was widely criticized by experts in genetics and bioethics who said they believed it was a violation of personal privacy and that it was illegal under an act passed by Congress that took effect in November 2009.

According to several people in baseball, the commissioner’s office has not conducted DNA testing since the practice was disclosed.

But was the earlier “genetic testing” was “a violation of personal privacy” and illegal under the Genetic Information Nondiscrimination Act”? It depends, I would submit, on the tests done. GINA was meant to prohibit tests for medically relevant conditions in employment and insurance. Its application — if any — to identity testing is discussed in the essay, GINA’s Genotypes. There, I argue that GINA should not prohibit an employer from testing potential or actual employees at the usual forensic identification loci. Of course, the privacy issue is more acute if the leagues were doing parentage testing, but even that is outside the strike zone of GINA.


David H. Kaye, Commentary, GINA’s Genotypes, 108 Mich. L. Rev. First Impressions 51 (2010), http://www.michiganlawreview.org/assets/fi/108/kaye2.pdf

Michael S. Schmidt, Baseball Considers Plan to Curtail Age Fraud, N.Y. Times, Feb. 10, 2010, at B11

Previous entries in this blog tagged with “GINA”