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SAMSI PROGRAM IN FORENSICS 2015RESEARCH TRIANGLE PARK, NC
PETER J. NEUFELDCO-DIRECTORINNOCENCE PROJECT
The Critical Need for Research Assessingthe Probative Value of Forensic Evidence
Upstream Remedies to Prevent Wrongful Convictions:
330 POST-CONVICTION DNA EXONERATIONS IN USA
Misapplication of forensic science contributed to approximately half of wrongful convictions overturned by DNA
MISAPPLICATION OF FORENSIC SCIENCE
74 of the total DNA exonerations included erroneous hair microscopy evidence as demonstrated by DNA testing (included both state and FBI hair comparisons)
A CRITICAL MASS OF EXONERATIONS
3 EXONERATIONS, 3 YEARS, 3 EXAMINERS
Donald Gates exonerated 2009
Kirk Odom exonerated in 2012
Santae Tribbleexonerated in 2012
In 2012, Spencer Hsu began an investigative series highlighting flawed forensic work by the FBI and the hair review project, including:• “Convicted defendants left uninformed of forensic flaws found by
Justice Dept.” (April 16, 2012)• “Forensic science not as reliable as you may think”
(April 17, 2012)• “Flawed forensics prompt case reviews” (July 10, 2012)
MICROSCOPIC HAIR COMPARISON
HISTORY OF MICROSCOPIC HAIR COMPARISON
FBI began performing hair comparison long before 1970s in effort to make probative match of unknown hairs to hairs connected to known suspect or victim.
• FBI Manual on Hair Microscopy (1977), at https://www.ncjrs.gov/pdffiles1/Digitization/78957NCJRS.pdf.
• Oien (2009) (stating that “[t]hese comparisons have been routinely conducted in forensic laboratories and accepted both in the scientific community and in the legal community for the past 75 years."
HISTORY OF MICROSCOPIC HAIR COMPARISON
Two relevant questions:Can a properly trained examiner determine that a questioned sample hair and a known suspect hair are similar (sometimes referred to as a positive association)? Can a properly trained examiner provide a scientifically valid estimate of the rareness or frequency of the similarity that you would find between two differently sourced samples?
HISTORY OF MICROSCOPIC HAIR COMPARISON
HISTORY OF MICROSCOPIC HAIR COMPARISON Myth:
Hair comparison is a 1:1 match where all characteristics are present on both the questioned and known hair.
Fact:There is rarely, if ever, a 1:1 match. Most cases involve a questioned hair being compared to dozens of hairs (“the sample hair”) from a suspect due to intra-individual variation. Thus, certain characteristics of the questioned hair might be present in one sample hair from a suspect and not in others, while other characteristics might be present in a different subset of sample hair(s) from the suspect.
2009 NAS REPORT: SCIENTIFIC LIMITS OF HAIR COMPARISON
“No scientifically accepted statistics exist about the frequency with which particular characteristics of hair are distributed in the population. There appear to be no uniform standards on the number of features on which hairs must agree before an examiner may declare a “match.” (p.160)
“The committee found no scientific support for the use of hair comparisons for individualization in the absence of nuclear DNA. Microscopy and mtDNA analysis can be used in tandem and may add to one another’s value for classifying a common source, but no studies have been performed specifically to quantify the reliability of their joint use.” (p.161)
Strengthening Forensic Science in the United States: A Path Forward, Committee on Identifying the Needs of the Forensic Science Community, The National Academies Press (2009)
FBI RESEARCH ILLUSTRATES THE PROBLEM
M. Houck and B. Budowle. Correlation of microscopic and mitochondrial DNA hair comparisons. Journal of Forensic Sciences 47(5), at 964-967 (2002)
11 percent of the cases in which the FBI hair examiners declared an “association”, mtDNA testing revealed that the hairs did not have a common source. 54 percent of the cases in which FBI hair examiners declared an “inconclusive” decision, mtDNA testing revealed were true exclusions
FBI HAIR REVIEW
REVIEW PROCESS
FBI / DOJ / NACDL / Innocence Project Collaboration (2012- ):
FBI Identified 21,000 cases where analysis was done by FBI before 2000; 3000 cases where FBI made positive associations between questioned hair and known sample;FBI conducts review of transcripts, shares results with NACDL/Innocence Project, FBI certifies results;Criteria for evaluating testimony was developed by FBI Lab with the input of statisticians. FBI makes final decision on presence of errors in each case.
APPROPRIATE NON-MISLEADING TESTIMONY
The examiner’s testimony appropriately reflected the fact that hair comparison could not be used to make a positive identification, but that it could indicate, at the broad class level, that a contributor of a known sample could be included in a pool of people of unknown size, as a possible source of the hair evidence (without in any way giving probabilities, as an opinion to the likelihood or rareness of the positive association, or the size of the class) or that the contributor of a known sample could be excluded as a possible source of the hair evidence based on the known sample provided.
TYPES OF INAPPROPRIATE TESTIMONY
Error Type 1: The examiner stated or implied that the evidentiary hair could be associated with a specific individual to the exclusion of all others.
ERROR TYPE 1
ERROR TYPE 1
ERROR TYPE 1
ERROR TYPE 1
TYPES OF INAPPROPRIATE TESTIMONY
Error Type 2: The examiner assigned to the positive association a statistical weight or probability or provided a likelihood that the questioned hair originated from a particular source, or an opinion as to the likelihood or rareness of the positive association that could lead the jury to believe that valid statistical weight can be assigned to microscopic hair association.
ERROR TYPE 3 & 2
Type 3
Type 2
ERROR TYPE 2
TYPES OF INAPPROPRIATE TESTIMONY
Error Type 3: The examiner cites the number of cases or hair analyses worked in the lab and the number of samples from different individuals that could not be distinguished from one another as a predictive value to bolster the conclusion that a hair belongs to a specific individual.
ERROR TYPE 3
ERROR TYPES 2 & 3
INITIAL RESULTS
• As of March 2015:• FBI reviewed approximately 500 cases•Of the 268 transcripts where examiners provided testimony to inculpate the defendant at trial, 96% (N=257) contained one or more types of testimonial errors. • All but two of 28 FBI examiners provided testimony that contained erroneous statements or authored lab reports with such statements. •The review showed that FBI examiners testified in 41 states.• 94% (N=33) of capital case testimony where associations were made had errors.
• 9 of these capital defendants executed• 5 of these capital defendants died of other causes
2015 Spencer Hsu article reveals FBI also trained thousands of state and local level hair microscopists.
These state and local examiners were trained by the FBI to use the same methods to reach the same conclusions and to give testimony containing the same errors as the FBI.How pervasive is the problem? Estimates of 500-1000 state and local microscopic hair comparison examiners were trained by the FBI to testify the same way.
KEY ISSUES:WHAT IS TO BE DONE?
KEY ISSUE
We are counting on your community to devise
1. Statistically appropriate - valid and reliable methods to assess the similarity or dissimilarity of two samples
2. Statistically appropriate - valid and reliable methods for interpreting and expressing to the jury the probative value of the forensic evidence
KEY ISSUE
We need to communicate the value of the evidence to lay jurors and judges in a way people will understand the evidence, and not distort it.
KEY ISSUE
What should be required of the expert when life and liberty are at stake?
THANK YOU