Forensic Testimony: “Matches”, An Over-Inference of Data? A Giglio Obligation?

Frederic Whitehurst

ABSTRACT: The expert witness who over-infers his data through the misuse of adjectives of comparison opens himself up to cross-examination that can and will discredit his work product. This paper uses the example of forensic analysis of black powder explosive to demonstrate that one can not categorically “match” one Black Powder sample to another or very often one complex chemical system to another and that even if this were possible, such “matches” may have limited probative value. The paper also explores the legal obligation of the expert to reveal to the prosecutor, court and trier-of-fact the limitations of the probative value of the evidence where those limitations might be considered to be exculpatory information.

Keywords: Black Powder, forensic analysis,


Ref: JPyro, Issue 11, 2000, pp53-62
(J11_53)

© Journal of Pyrotechnics and CarnDu Ltd



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