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RECENT TRENDS IN FIREARMS/TOOLMARKS. June 05, 2012. Ronald L. Singer, M.S. Tarrant County Medical Examiner’s Crime Laboratory Fort Worth, Texas. FIRST, A REFRESHER. FIREARMS IDENTIFICATION. Ammunition Component Comparison Firearm Function Gunshot Residues on Clothes & Hands

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Presentation Transcript
recent trends in firearms toolmarks

June 05, 2012

Ronald L. Singer, M.S.

Tarrant County Medical Examiner’s

Crime Laboratory

Fort Worth, Texas

firearms identification


  • Ammunition Component Comparison
  • Firearm Function
  • Gunshot Residues on Clothes & Hands
  • Muzzle to Target Distances
  • Serial Number Restoration
firing process
  • Primer explodes
  • Powder ignites
  • Gases build up
  • Bullet is pushed from cartridge case to back of barrel
  • Bullet is forced down the barrel by the expanding gases
  • Cartridge case is slammed against breech face
  • Imperfections in barrel and on breech face are transferred to surfaces of bullet and cartridge case
firing process 2
  • Metal vapors, inorganic vapors from explosion and heating are driven out of cylinder gap, ejection port, etc. at high velocities
  • Vapors cool, condense
  • Bullet exits muzzle
  • Muzzle flash
  • Gases, burning gunpowder and gunshot residue exit muzzle, expand in atmosphere


Frye / Daubert Challenges Based on NAS Report


Firearms/Toolmarks in Report

  • Six pages (150 – 155)
  • Theory, presence in labs
  • Brief history of database issues
  • Analytical methods
  • Interpretation

“… even with more training and experience using newer techniques, the decision of the toolmark examiner remains a subjective decision based on unarticulated standards and no statistical foundation for estimation of error rates.” (pg. 153-154)

“A fundamental problem with toolmark and firearms analysis is the lack of a precisely defined process.” (pg. 155)


First, and most significantly, this study is neither a verdict on the

uniqueness of firearms-related toolmarks generally nor an assessment of the

validity of firearms identification as a discipline.


“Underlying the specific tasks with which the committee was charged

is the question of whether firearms-related toolmarks are unique: that is,

whether a particular set of toolmarks can be shown to come from one

weapon to the exclusion of all others. Very early in its work the committee found that this question cannot now be definitively answered.”

Finding: The validity of the fundamental assumptions of uniqueness

and reproducibility of firearms-related toolmarks has not yet been fully demonstrated.


U.S. v. Nelson Otero and Maxcime Cagan

Criminal No. 11-23 (SRC)

U.S. District Court of New Jersey

March 15, 2012

Separate Daubert motions by both Defendants to exclude expert testimony by firearms expert. Both denied.

“… Deady’s expert report and opinion are admissible under Rule 702.”

“… the Court concludes that the Government has demonstrated that Deady’s proffered opinion is based on a reliable methodology. The Court recognizes … that the toolmark identification procedures … do indeed involve some degree of subjective analysis and reliance upon the expertise and experience of the examiner. The Court further recognizes … that claims for absolute certainty … may well be somewhat overblown.”


May 2010 – May 2012

Nineteen additional challenges

  • U.S. v Louis McIntosh S2-11-CR-500 (KMK) 02/2012
  • CA v Joseph Blacknell 5-110816-6 01/2012
  • KS v Antwon Pierce 10-CR-383 12/2011
  • IN v Desmond Turner 49S00-0912-CR-565 09/2011
  • U.S. v Ricardo Jones 08-CF-716 09/2011
  • FL v Alwin C Tumblin 2004-CF-3127 08/2011
  • U.S. v Adrian Mendiola 10-00037 05/2011
  • NY v Jose Guadelupe 09-513 04/2011
  • CA v Gumaro Baez 560543A 02/2011
  • MA v Pytou Heang SJC-10376 02/2011
  • U.S. v Love 2:09-CR-20317-JPM 02/2011
  • NC v Demetrius Hairston 08-CRS-60908 01/2011
  • TX v Thai-An Nguyen F08-45280 01/2011
  • U.S. v Cerna CR-08-0730 09/2010
  • CA v David Carter 157693 07/2010
  • WI v Christopher Jones 2009-AP-2835-CR 08/2010
  • U.S. v Anderson 2009 CF1 20672 09/2010
  • U.S. v Marius St. Gerard APO AE 09107 06/2010
  • WA v Daylan Erin Berg 09-1-00761-6 05/2010 *
  • WA v Jeffery Scott Reed 09-1-00762-4 05/2010 *

Eighteen allowed firearms testimony; five with restrictions:

Mendiola – Judge ruled that identification could not be stated as “… to the exclusion of all others …”

Heang – Examiner’s conclusion should be based on certainty level that conveys “…to a reasonable degree of ballistic certainty…”

Love – Examiner could not testify to the absolute or practical certainty of his results.

Anderson – Examiner could declare a firearms “match” to a “reasonable degree of certainty within the field of firearms identification,” or to a “practical certainty” but may not opine that it is a “practical impossibility” or a “virtual impossibility” that another firearm could have imparted the markings.

Berg & Reed – Expert could testify as to “his opinion based on a reasonable degree of certainty in the ballistics field…” and that expert could not advise of any statistical evidence or present probabilities of a match.


United States v Marius St. Gerard

APO AE 09107

U.S. Army Trial Judiciary, Fifth Judicial Circuit, Germany

Defense moved to exclude the opinion of the firearm examiner that a specific cartridge case was fired by a specific AK-47

“Considering the Daubert factors in light of Mrs. Sevigny’s anticipated testimony, the Court finds that any testimony indicating that the shell casing must have come from the AK-47 would be unreliable. While it is clear that Mrs. Sevigny has training and expertise in identifying toolmarks that would undoubtedly assist the trier of fact in this case, the subjective nature of the process,

lack of quantitative standards, and limited scope of foundational testing do not demonstrate the scientific principles necessary to establish the origin of the marks with any specific amount of certainty.”

thank you


Tarrant County Medical Examiner’s Office

Fort Worth, Texas USA