What’s on the Net – The WhiteHouse Science Council on forensics – bites, firearms, shoes, tires, DNA

President Obama meets with PCAST

The usual complaints about the WH “non-forensic” reviewers (from the likes of The Fraternal Order of Police)  are reminiscent of responses to the 2009 National Academy of Science report on “Strengthening Forensic Science.” Yesterday’s announcement from the White House Science Council ” (AKA PCAST) urged  federal prosecutors not to admit into courts these heavily used and police developed (except for DNA) matching methods.

One more group very involved in the prosecutorial use of these methods is the US Department of Justice. There will be a battle-royal going on soon at  PCAST. The DOJ is the big hitter in the US’s prosecution and its aligned National Institute of Justice forensic training groups and forensic funding.

One telling motivator for the WH is wrongful convictions.

“It has become apparent, over the past decade, that faulty forensic feature comparison has led to numerous miscarriages of justice,” according to the draft report  dated September 2016. “It has also been revealed that the problems are not due simply to poor performance by a few practitioners, but rather to the fact that the reliability of many forensic feature-comparison methods has never been meaningfully evaluated.”

Here’s a look at  the WH group thinkers who reviewed various forensic tasks. PCAST will, “in a few weeks,” report in order to  dramatically advance forensic improvements.

“PCAST consists of 20 of the nation’s leading scientists and engineers, appointed by the President to provide direct advice to him and the White House on important matters of science and technology. PCAST has recently begun to explore how best to ensure the quality of forensic science, based on reliable scientific principles and methods, within the criminal justice system. PCAST members are interested in hearing from the broad stakeholder community on each of the questions listed below in an effort to better understand the landscape of this topic.”

Here’s some web links and comments on what’s going on.

White House panel expected to issue report critical of some forensic evidence in criminal cases. LA Times.

Group sees lack of science behind much of bite-mark, hair, footwear, firearm and footwear analysis.  Wall St. Journal. 

And here is a discussion thread from some significant forensic and legal people on the PCAST announcement.

  1. Tire treads!!! But what about My Cousin Vinnie?  (Great movie.)Seriously, I think this will be a big deal, especially the multiple source DNA and maybe the firearm tool mark (though I don’t know enough to know how often that is used, or even quite exactly what it means.)
  2. DNA mixtures are the norm.  I can guarantee that this will create an enormous effect because, if enacted, will disallow most DNA evidence.  While I am overall happy that this difficult area will receive more scrutiny, there is a danger that some fairly simple mixtures (e.g. vaginal swabs with victim + suspect) may be caught in the trap..
  3. If this is actually happening, it is huge.  And long overdue.  And Allan, I doubt they’ll include simple mixtures — my guess is that it will be about multi-person mixtures where the template is such that it’s essentially low copy.
  4. That’s a difficult line to draw.
  5. The whole thing is sort of weird.  Even the terminology is weird (first time I ever saw the term “expended bullet casings.”   And of course, it is much too global and not sufficiently task specific.  I can accept this in regard to bite mark, but I can give you plenty of examples of very persuasive and well-warranted assignment of expended shell casings to particular weapons, especially those that have gone through semi-automatic pistols and have the whole collection of marks generated by that process (firing pin, extractor, ejector, etc).  This would throw out such assignment of source even when a particular firing pin was so worn or misshapen that the likelihood of another source, while not mathematically characterizable, was vitually nil.  And we must remember that such information can be exculpatory as well as inculpatory. While circumspection is called for, and more research needed, firearms examiners have done pretty well in black box tests, I believe.  And they have categorically distinguished, apparently, between shell casings and bullet striations (which were not covered), which seems unwarranted to me.
  6. If complex DNA mixes not allowed but software loved by DAs, what then? See Allegheny County: DAs send out samples for own analysis. Better?
  7. I think many forensics have deep science basis, just not been explicated. Not allowed by cops; no funding; no remorse: What did you expect?
  8. Listening to the PCAST meeting. IMHO, forensics did it to themselves but couldn’t help it because police ran things. We weren’t real science.
  9. And why recommend more research $ to FBI: Aren’t they the source of most forensic failures? Bullet lead, hairs, mixtures, 0% error…
  10. Hooray for Science!
    Hooray for an administration that believes in science!
  11. [We have] written a lot about the lack of science in firearm/toolmark practice.  See the attached as examples [omitted].  In Israel shoeprint examiners cannot claim they are a scientist but rather they are practitioners.  Plumbers and hair stylists are also practitioners and if they are successful they typically know their trade.  They are all very useful to society.  So if tool mark examiners say that they are working on making their field a science, there is no problem.  They should work with relevant mainstream sciences:  physics, metallurgy, statistics, and human factor experts for example. If they take such a path then in 20 years or so the successor to pcast may say they are a science.  In the interim, it can be suggested to them that they take the Israeli route and call themselves forensic practitioners and not forensic or any other kind of a scientist.





About csidds

Dr. Michael Bowers is a long time forensic consultant in the US and international court systems.
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