Suspect Evidence and Coalmine Canaries

58 Pages Posted: 24 Jul 2018 Last revised: 27 Sep 2018

See all articles by Russell D. Covey

Russell D. Covey

Georgia State University College of Law

Date Written: 2018


In recent years, it has become increasingly obvious that certain types of evidence commonly used in serious criminal cases, including microscopic hair comparison, bitemark comparison, and jailhouse informants, are deeply unreliable. For those close to the system, this is not likely all that surprising. Few with even a passing understanding of forensic practice would be have been shocked to learn that bite-mark evidence, for instance, is untrustworthy. The thesis of this paper is that use of formally admissible but facially unreliable evidence is an indicator that something might be amiss in the case. This study explores the hypothesis that use of certain types of unreliable evidence – such as jailhouse informants – acts as evidentiary “canaries in the coalmine,” indicating overly aggressive and potentially improper police and prosecutorial conduct.

To test this hypothesis, the study uses data drawn from the National Registry of Exonerations database and from published cases available in online databases to examine correlations between various factors associated with wrongful convictions and indications of official misconduct. The results demonstrated a strong inverse correlation between the reliability of evidence used to obtain a conviction and the likelihood of official misconduct. Misconduct claims were far more likely to occur where prosecutors relied at trial on evidence that they knew or had reason to suspect was unreliable. In contrast, in cases where the inculpatory evidence had a relatively high degree of apparent reliability, misconduct claims or findings occurred with correspondingly less frequency. Specifically, the study identifies three types of suspect evidence: jailhouse informants, microscopic hair comparison, and bitemark comparison as strong potential indicators of official misconduct.

The results of this study should provide researchers searching for clues regarding the causes of wrongful convictions, and innocence lawyers seeking to identify plausible wrongful conviction cases, with an important new tool to help allocate scarce investigatory resources.

First published by Georgetown University in the American Criminal Law Review.

Keywords: criminal procedure, exoneration, evidence, forensic evidence, forensic science, criminal law, hair evidence, bitemark evidence, jailhouse informants

JEL Classification: K14, K19, K41, K42

Suggested Citation

Covey, Russell D., Suspect Evidence and Coalmine Canaries (2018). American Criminal Law Review, Vol. 55, 2018; Georgia State University College of Law, Legal Studies Research Paper No. 2018-20. Available at SSRN:

Russell D. Covey (Contact Author)

Georgia State University College of Law ( email )

P.O. Box 4037
Atlanta, GA 30302-4037
United States
404-4413-9182 (Phone)
404-413-9225 (Fax)

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