Can DNA really prove much?

[I]t is relatively straightforward for an innocent person’s DNA to be inadvertently transferred to surfaces that he or she has never come into contact with. This could place people at crime scenes that they had never visited or link them to weapons they had never handled.”

In discussing United States v. Henning, No. 20150410 (A. Ct. Crim. App. Sep. 3, 2015), a good friend had this to say about the case and about DNA examinations which are common in military sexual assault cases.

There are many problems with this opinion.

He notes that:

The KC lab has had problems in the past relevant here, e.g., “chain-of-custody,” sealing and storage issues as noted HERE, staffing issues, noted HERE, etc.

He notes then the general purpose behind evidence such as DNA results.

The logical and legal purpose of using DNA evidence is to do one of two things: either match the DNA to a specific individual, or to exclude someone from the universe of potential matches.  The DNA “results” in this case can do neither, so therefore, how can they be relevant under MRE 401?  To “conclude” that the Accused could “not be excluded” is a nonsensical statement – other than the sample was too small to draw any scientific conclusions – which is after all why DNA testing is done in the first place.

Indeed, as the FBI itself states:

Nuclear DNA (nDNA) is the most discriminating and is typically analyzed in evidence containing body fluids, skin cells, bones, and hairs that have tissue at their root ends. The power of nDNA testing lies in the ability to identify an individual as being the source of the DNA obtained from an evidence item, or by excluding an individual as a contributor to the DNA evidence. LINK

He then notes the age-old question of how much “information” do you need to declare a “match.”  This is a similar question asked when deciding whether or not fingerprints “match.”  How many points of concordance are needed for a scientifically reliable match.

The FBI also set a minimum standard for DNA “matches” i.e., ” For Forensic STR DNA analysis, the DNA profile consists of one or two alleles at the 13 CODIS Core Loci.” LINK.  Here, they only had enough DNA to be examined at 4 loci – less than 1/3 of the minimum FBI standard – and again, it’s an attempt to make this “relevant” when it is not.  If only one allele at any of the other standard 9 loci is different, then he IS excluded but that data is not available due to the lack of sample size.
But, like other FBI forensic screw-ups, e.g., hair comparison analysis, bullet-lead comparison analysis, etc., the FBI has had another “Whoops, we goofed” moment recently with DNA comparison statistics – one of the major issues here.  That data is available

So, he asks, is the opinion offered here based on reliable science or knowledge.  It appears it doesn’t satisfy the requirement of general acceptance.

Strangely, the purported “alleles present statistic” used by the KC Lab people, does not appear to be scientifically recognized by anyone except the 2 people testifying for the government. If you “Google” “alleles present statistic” the only hit that shows up is a link to the opinion in this case. But, the decision here not only does not describe whatever this is, or how it was applied in this case.

Next he gets to a common issue we see in military sexual assault cases—mixed samples, hers and his or them.

DNA “mixture” cases are equally as problematic – something that the DNA testing here could neither confirm nor refute. LINK.
Considering the miniscule sample size and thus, inability to examine the 13 CODIS loqi, secondary (or even tertiary) transfer cannot be ruled out, i.e., “cannot be excluded.”  For example, the Accused could have been sitting on a couch, with his hands on it depositing his epithelial cells (containing DNA) on the couch. Then if the complainant’s underwear were placed on that spot on the couch, those cells could easily transfer to the underwear, as Zach appropriately notes above.  Indeed, one can hypothesize that MAJ H went to the bathroom to urinate and like a good guest, lifted up the toilet seat, did his thing, and then put the seat down again depositing his epithelial cells on the seat. There after, if the complainant then sat on that same toilet seat, a reasonable and logical transfer from the seat to her butt to her underwear is quite feasible.
Lastly, ACCA’s MRE 403 analysis [p. 10-11], leaves much to be desired as it simply ignores the purpose behind 403’s balancing requirement. E.g., ACCA notes that “any evidence that MAJ H is a possible contributor, even to a small degree, would still be highly probative.”  But that’s the problem – there is simply no evidence that he is a possible contributor! It is pure speculation based upon 5 alleles at 4 loqi and why it proves nothing in the context of a DNA “match.”

He concludes:  When you are asking the fact-finder to speculate or assume or guess that there’s a “possible match,” without any science or evidence to back up that conclusion, that’s “unfair.”  There may be no “mini-trial” but there’s a great “probability” of a 3-ring circus.

Thank you Dew_Process for this.

One hopes that the Appellant will petition the Court of Appeals for the Armed Forces and that they will take the case.

In the meantime, consider a H challenge to the DNA as well as a challenge under Mil. R. Evid. 401 and 403.

In October 2015, the Texas Forensic Science Commission raised concerns about the accuracy of the statistical interpretation of DNA evidence.

Despite how it is often portrayed, in the media and in courts, the forensic science of DNA is far from infallible. Particularly concerning is that police and prosecutors now frequently talk of ‘touch DNA’ — genetic profiles of suspects and offenders that have been generated in a laboratory from just a handful of skin cells left behind in a fingerprint.

Research done at the University of Indianapolis in Indiana has highlighted how unreliable this kind of evidence can be.

SeeCynthia M. CaleForensic DNA evidence is not infallible.  526 NATURE 611 (29 October 2015).