Tuesday, October 18, 2011

New Mexico Supreme Court Proposes Rules on Lab Reports

The New Mexico Supreme Court is soliciting comments on "three representative proposals that have been suggested . . . to address the admission of state laboratory forensic analyses in light of Bullcoming." [1] The state court is referring to the U.S. Supreme Court's somewhat unenlightening opinion in Bullcoming v. New Mexico, 131 S. Ct. 2705 (2011), discussed here some months ago. Inasmuch the the rules are a response to a Confrontation Clause decision that applies only in criminal cases, I shall assume that these rules also would apply solely in criminal cases.

The first proposal covers all "forensic scientific evidence including blood and breath alcohol test reports, controlled substance chemical analysis reports." It orders the parties to confer about stipulating to a waiver of the defendant's right to be presented with a laboratory analyst to cross-examine on the laboratory's findings and of the state's right to present a live witness along with the reports. [1]

Of course, the parties can initiate such such discussions now, and they need not stipulate to anything anyway. The proposed rule states that "The report or print-out ... shall not be admitted at trial without the testimony of necessary witnesses unless the defendant stipulates in writing," but that adds nothing of substance to the status quo (or to the rest of the rule).

But what happens if one or more of the parties do not event want to talk about a stipulation. The rule says that "[i]f either party cannot obtain the opposition’s position regarding a proposed stipulated order, that party may file a motion requesting a hearing to determine the opposition’s position regarding the need for testimony ... ." Maybe the judge can induce the parties to take an irrevocable position well before the trial, as the rule seems to contemplate. This might help the lab schedule its staff time, but is all this judicial rule-making worth the effort to achieve this convenience?

Alternative Rule 2 abolishes the hearsay rule as applied to "a written report of the conduct and results of a chemical analysis of breath or blood for determining blood alcohol concentration." Of course, many jurisdictions have statutes to this effect, and others apply the business records exception to reach the same result. The (new?) hearsay exception makes no difference in New Mexico criminal cases as long as the U.S. Supreme Court adheres to the interpretation of the Confrontation Clause articulated in Crawford v. Washington, 541 U.S. 36 (2004).

Alternative 3 requires the prosecution to serve on the defendant "[a] copy of a report of the methods and findings of any examination conducted by an employee of any governmental laboratory ... no later than ninety (90) days before trial" and to give notice to the defense at the same time if it intends to introduce the report into evidence. If New Mexico prosecutors do not already provide timely disclosure of reports or if this provision requires that more complete reports be prepared than is currently the practice, it would be a significant improvement.

Yet, the rule also imposes a burden on the defense to object in writing before trial. In this regard, it reads as follows: "If the defendant does not file a written objection with the court to the use of the laboratory report and certificate within the time allowed by this subparagraph, then the report and certificate are admissible in evidence."

The thinking seems to be that the defense ordinarily should not have to object before trial. However, if the prosecution affirmatively notifies defense counsel that it does not plan to present a necessary witness, then the defense should be forced to make a pretrial demand for confrontation (or lose that right). The rule would require the defendant to give notice at least 30 days before trial. [3] A dictum in Melendez-Diaz v. Massachusetts, 129 S. Ct. 2527 (2009), approves of such notice-and-demand rules. [4]

Interestingly, none of the proposed rules go so far as to place the burden on the defendant to give notice in all cases in which it learns that a laboratory report exists. The state rules committee's commentary to the first alternative rule states: "This rule applies in lieu of a notice and demand rule, which the committee rejected, and is meant to ensure that the waiver is not made by accident or lack of knowledge. The defendant may waive this right by stipulated order, but the waiver shall be made willingly, knowingly, and intelligently."


1. Myrna Raeder initiated a discussion of these rules on Roger Park's discussion list for law professors. The rules are available at http://nmsupremecourt.nmcourts.gov/rules/pdfs/proposed_alt._rules_1,_2,_3.pdf

2. The proposed rule states that "[t]he parties shall confer and either party may file a stipulated order to admit a report or print-out of results ... or to limit the witnesses required to appear at trial."

3. This proposed rule include the statement that "[i]f the defendant does not file a written objection with the court to the use of the laboratory report and certificate within the time allowed by this subparagraph, then the report and certificate are admissible in evidence ... ."

4. See http://federalevidence.com/node/1228; http://www.scotusblog.com/case-files/cases/briscoe-v-virginia-2/.

Thursday, October 6, 2011

DNA Identification Technology: Fast and Furious

Today’s talks at the International Symposium on Human Identification indicated some directions in which DNA-based identification technology will move in the near future. For example, one company reported a way to type 26 different STRs simultaneously. Is that enough to justify testimony of global individualization (with the exception of identical twins)?

The Departments of Defense, Homeland Security, and Justice are seeking self-contained devices for rapid STR profiling and interpretation, and several companies claim to be on the verge of delivering them. “Rapid” means an hour or so, and the hope is that these microfluidic devices will permit on-the-spot (or at-the-police-station) results for investigations as well as DNA database queries and entries. One company promises a functioning product in April 2012. Another refers to an existing instrument “compact enough to be used in an office setting, airport security area, mobile van, or field-forward military site.”

None of these has been fully validated. The FBI is figuring on widespread implementation at local police stations in 4-7 years, but police in Palm Bay, Florida, have posted videos on YouTube to advertise their success with a microfluidic device in “Operation Rapid Hit.”

Finally, companies are supplying police with phenotype and ancestry data, including probable eye and hair color. For the future, the most impressive -- and disquieting -- approach uses “next-generation sequencing” to extract all the usual STRs, together with phenotypically and medically informative data in one fell swoop.

Indeed, sequencing the oral bacteria that we host is possible. A speaker described one individual whose microbiome included a bacterium used in the industrial production of yogurt and cheese. Just imagine the APB: “The suspect is a white male with brown hair (probability = 0.45) and blue eyes (probability = 0.95) who likes yogurt.”

Tuesday, October 4, 2011

An Odd Set of Odds in Kinship Matching with DNA Databases

The 22d International Symposium on the Future of Human Identification began yesterday with a set of workshops. One was on "familial searching." The phrase refers to trawling the profiles in a DNA database for certain types of partial matches to a DNA profile from a crime-scene sample.

Partial matches that are useful in generating investigative leads to family members arise much more often when a particular kind of relative (say, a full sibling) is the source of the crime-scene sample than when an individual who is not closely related to the database inhabitant is the source. The ratio of the probability of the partial match under the former condition (a given genetic relationship) to the latter (unrelated individuals) is a likelihood ratio (LR). The LR (or, technically, its logarithm) for siblingship expresses the weight of the evidence in favor of the hypothesis that the source is full sibling as opposed to an unrelated individual.

After explaining the this idea, the first speaker presented the following formula:
"Odds" = LRautosomal x LRY-STR x 1/N         (1)
She attributed this formula to the California state DNA laboratory that does familial searching in that state. In this equation, N is the size of the database, LRautosomal is the likelihood ratio for the partial match at a set of autosomal STR loci, and LRY-STR is the likelihood ratio for the matching Y-STR haplotype.

She described this as a Bayesian computation that could lead to statements in court such as "there is a 98% probability" that the person whose DNA was found at the crime scene is a brother of Joe Smith, a convicted offender whose DNA profile is in a DNA database.

There are three interesting things to note about these suggestions. To begin with, it is not clear why such a statement would be introduced in a trial. By the time the suspect has become a defendant, a new sample of his DNA should have been tested to establish a full match to the crime-scene sample. At that point, why would the judge or jury care whether defendant is related to a database inhabitant. The relevance of the DNA evidence lies in the full match to the crime-scene sample, and the jury need not consider whether the defendant is a relative of someone not involved in the alleged crime. (One might ask whether the trawl through the database somehow degrades the probative value of the full match, but, if anything, it increases it. [1])

The issue could arise, however, if police were to seek a court order or search warrant to collect a DNA sample from the suspect. At that point, they would need to describe the significance of the partial match to the convicted offender.

This possibility brings us to the second noteworthy point about equation (1). The "odds" (or the corresponding probability) are not the way to present the weight of the partial match. Consider the prior probability of a match in a small database, say, of size N=2. Prior to considering the partial match, why would one think that the probability of a database inhabitant being the sibling of the criminal who resides outside the database is 1/N = 1/2? It is quite improbable that the database of two people includes a relative of every criminal who leaves DNA at a crime-scene. The a priori probability for a small database must be closer to 0 than 1/N.

That the prior probability is less than 1/N is a general result. The only exception occurs when it is absolutely certain that a sibling of the perpetrator is in the database. On that assumption, prior odds of 1 to N-1 are not unreasonable. But that assumption is entirely artificial, and to advise a magistrate that the posterior odds have the value computed according to (1) would be to overstate the implications of the partial match.

The third thing to note about dividing by N is that it accomplishes nothing in producing a viable list of partially matching profiles in a DNA database trawl. The straightforward approach is to produce a short list of candidates in the database whose first-degree relatives might be the source of the crime-scene sample. The minimum value of LRautosomal x LRY-STR should be large enough to keep the two conditional error probabilities (including a candidate when there is no relationship, and not including a candidate when there is a relationship) small. This threshold value does not depend on N. (A later speaker made this observation.)

Equation (1), it seems, is useless. Instead, the magistrate should be told the value of the LR and how often such large LRs would occur when a crime-scene sample comes from a relative versus how often it would occur when it comes from an related person.


1. David H. Kaye, 2009, Rounding Up the Usual Suspects: A Legal and Logical Analysis of DNA Database Trawls, North Carolina Law Review, 87(2), 425-503.