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Firearms and Tool Mark Identification

Firearms and Tool Mark Identification. Responding to Recent Criticisms - Ronald Nichols, ATF FSL - SF. Joan Griffin and David LaMagna. Daubert Challenges to Forensic Evidence: Ballistics Next on the Firing Line – The Champion , September/October 2002, 20-23; 58-62. Michael Saks.

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Firearms and Tool Mark Identification

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  1. Firearms and Tool Mark Identification Responding to Recent Criticisms - Ronald Nichols, ATF FSL - SF

  2. Joan Griffin and David LaMagna • Daubert Challenges to Forensic Evidence: Ballistics Next on the Firing Line – The Champion, September/October 2002, 20-23; 58-62.

  3. Michael Saks • Implications of the Daubert Test for Forensic Identification Science – Shepard’s Expert and Scientific Evidence, 1(3), Winter 1994, 427-432. • The Coming Paradigm Shift in Forensic Identification Science – Science, August 5, 2005, 892-895 with Koehler

  4. Adina Schwartz • A Challenge to the Admissibility of Firearms and Toolmark Identifications: Amicus Brief Prepared on Behalf of the Defendant in United States v. Kain, Crim. No. 03-573-1 (E.D. PA. 2004) – The Journal of Philosophy, Science & Law, Volume 4, December 2004.

  5. Adina Schwartz • A Systemic Challenge to the Reliability and Admissibility of Firearms and Toolmark Identification – The Columbia Science and Technology Law Review, Volume VI, 2005.

  6. Lisa Steele • “All We Want You to Confirm is What You Already Know” A Daubert Challenge to Firearms Identification – Criminal Law Bulletin.

  7. Schwartz Columbia STLR Article • Addresses Concerns Raised by Others in Comprehensive Format

  8. Common Themes • Scientific Reliability • Lack of Representative Databases • Lack of Statistical Treatment • Lack of Adequate Proficiency Testing • No Defined Error Rates • Current Computerized Technology Does Not Answer the Questions

  9. Scientific Reliability • Individual Characteristics are Comprised of Non-Unique Marks • Subclass Characteristics May be Confused with Individual Characteristics • Individual Marks on a Particular Tool Change Over Time

  10. Representative Databases • Like DNA • Issue Broached by Dr. S. Bunch, “Consecutive Matching Striation Criteria: A General Critique.” Journal of Forensic Science, Vol. 45, No. 5, September 2000, 955-962.

  11. Statistical Treatment • Like DNA • Issue Addressed by Dr. S. Bunch, “Consecutive Matching Striation Criteria: A General Critique.” Journal of Forensic Science, Vol. 45, No. 5, September 2000, 955-962.

  12. Proficiency Testing • Not Representative • Inadequate and Ineffective Administration of Tests to Examiners • Examiner Bias

  13. Error Rates • Like DNA • Claims of Infallibility and Absolute Identifications

  14. Computerized Technology • Does Not Address Needs of Representative Databases and Statistics

  15. Scientific Foundation Established • Discipline firmly rooted in application of the Scientific Method • Repeated testing of hypotheses related to identification has been performed • Has resulted in standard statement settings guidelines for defining identification criteria

  16. AFTE Theory of Identification* • IS a standard defining identification criteria • IS established as a theory based on principles of the scientific method • IS a statement of the relevant scientific community • NOT referenced by any recent criticisms * Theory of Identification, Range of Striae Comparison Reports and Modified Glossary Definitions – an AFTE Criteria for Identification Committee Report. AFTE Journal, 24(2), April 1992, 336-340.

  17. AFTE Theory of Identification • Addresses issues of common origin • Defines observational objectives • Defines sufficiency of agreement to establish common origin, i.e., identification criteria • Defines meaning of identification • Defines role of subjectivity

  18. Common Origin • “The theory of identification as it pertains to the comparison of tool marks enables opinions of common origin to be made when the unique surface contours of two tool marks are in ‘sufficient agreement’.”

  19. Observational Objectives • “Specifically, the relative height or depth, width, curvature and spatial relationship of the individual peaks, ridges and furrows within one set of surface contours are defined and compared to the corresponding features in the second set of surface contours.”

  20. Identification Criteria • “Agreement is significant when it exceeds the best agreement demonstrated between tool marks known to have been produced by different tools and is consistent with the agreement demonstrated by tool marks known to have been produced by the same tool.”

  21. What an Identification Means • “The statement that ‘sufficient agreement’ exists between two tool marks means that the agreement is of a quantity and quality that the likelihood another tool could have made the mark is so remote as to be considered a practical impossibility.”

  22. Subjectivity • “Currently the interpretation of individualization/identification is subjective in nature, founded on scientific principles and based on the examiner’s training and experience.”

  23. Scientific Reliability Issues of Contention – Part 1: Individual Characteristics are Comprised of Non-Unique Marks

  24. Individual Marks Comprised of Non-Unique Marks • The contention – “As a result of the overlapping individual characteristics of toolmarks made by different tools, examiners who assume that a certain amount of resemblance proves that the same tool produced both test and evidence toolmarks may be wrong…”* *Schwartz, Columbia STLR, p. 6.

  25. Individual Marks Comprised of Non-Unique Marks • The issue – Identification Criteria • Addressed by • Theory of Identification • Methodology • Extensive scientific studies • Individual training, experience and expertise

  26. Theory of Identification • Identification criteria has two parts • exceeds the best agreement demonstrated between tool marks known to have been produced by different tools • and is consistent with the agreement demonstrated by tool marks known to have been produced by the same tool

  27. Methodology • Comparative examinations are an efficient means by which examiners can observe and easily document through photomicrography similarities and differences between patterns of tool marks

  28. Scientific Studies* • Controlled studies pursued according to the tenants of the scientific method • Have included an assortment of tools and tool manufacturing processes • Have included tools known to have been manufactured consecutively • Have all supported appropriateness of the Theory of Identification *Two review articles include, Nichols, R. “Firearm and Toolmark Identification Criteria: A Review of the Literature,” JFS 42(3), 466-474 and “Firearm and Toolmark Identification Criteria: A Review of the Literature – Part 2.” JFS 48(2), 318-327.

  29. Individual Training and Experience • Vital to examiner’s ability to properly interpret observed correspondence • Gained through hours of microscopic comparisons directed at gaining familiarity of correspondence to be expected in known non-match situations of striated and impressed tool marks

  30. Contention – Small Tool Marks • Schwartz - See e.g., John E. Murdock…(stating that a “considerable amount of agreement” among striated toolmarks made by different tools is especially likely to be found “if the width of the mark being compared is quite small [say, two millimeters or less]”)…* *Schwartz, at 6-7, n. 13.

  31. Contention – Small Tool Marks • Murdock never said or implied this* • 2mm mark came from Butcher & Pugh+ and had nothing to do with expected high likelihood of similarity, but rather was simply defined as the size of a mark likely to have enough individual detail to permit a determination of common origin *Murdock, J.E. “Some Suggested Court Questions to Test Criteria for Identification Qualifications.” AFTE Journal, 24(1), 69-75. +Butcher, S. and Pugh, D. “A Study of Marks Made by Bolt Cutters.” JFSS, 15(2), 120.

  32. Contention – High Percentage of Matching Striations in KNM • Screwdrivers • Schwartz – up to 25% • Reference is Burd and Kirk* in which the 25% is from a single KNM comparison and in which they say the number of matching striations (irrespective of position) as a whole is a poor indicator because tool marks can have high line densities that would logically result in more coincident matching of striations *Burd, D. and Kirk, P., “Tool Marks: Factors Involved in Their Comparison and Use as Evidence,” Journal of Police Science, 32(6), 465.

  33. Contention – High Percentage of Matching Striations in KNM • Bolt Cutters • Schwartz – 28% • Reference is Butcher and Pugh* in which the 28% is the highest of a total of 880 KNM comparisons in which only three approached the level of 28% *Butcher, S. and Pugh, D. “A Study of Marks Made by Bolt Cutters.” JFSS, 15(2).

  34. Contention – High Percentage of Matching Striations in KNM • Bullets • Schwartz – 15-20% • Reference is Biasotti* who said, “…even under such ideal conditions the average percent match for bullets from the same gun is low and the percent match for bullets from different guns is high, which should illustrate the limited value of percent matching lines without regard to consecutiveness.” *Biasotti, A., “A Statistical Study of the Individual Characteristics of Fired Bullets.” JFS, 4(1).

  35. Scientific Reliability Issues of Contention – Part 2: Subclass Characteristics May be Confused with Individual Characteristics

  36. Subclass Characteristics • Defined as “Discernible surface features of an object which are more restrictive than CLASS CHARACTERISTICS in that they are: (1) Produced incidental to manufacture; (2) Are significant in that they relate to a smaller group source (a subset of the class to which they belong); (3) Can arise from a source which changes over time. Examples would include: bunter marks, extrusion marks on pipe, etc. Caution should be exercised in distinguishing subclass characteristics from INDIVIDUAL CHARACTERISTICS”* *“Theory of Identification, Range of Striae Comparison Reports and Modified Glossary Definitions – an AFTE Criteria for Identification Committee Report.” AFTE Journal, 24(2), 336-340.

  37. Subclass Characteristics • The contention – “A tool may also be wrongly identified as the source of a toolmark it did not produce if an examiner confuses subclass characteristics shared by more than one tool with individual characteristics unique to one and only one tool.”* *Schwartz, p. 8.

  38. Subclass Characteristics • The issue – potential for confusion with individual characteristics • Addressed by • Studies of manufactured tools • Knowledge of manufacturing processes • Knowledge of tool use and how it relates to orientation of any potential subclass characteristics

  39. Newly Manufactured Tools • The contention – “Despite their knowledge of this variation, firearms and toolmark examiners have not formulated any generalizations or statistics about which types of tools can be expected to produce toolmarks with subclass or individual characteristics when they are newly manufactured.”* *Schwartz, p. 9.

  40. Newly Manufactured Tools • Nineteen different references address the issue of subclass characteristics • These references allow examiners to move from knowledge of manufacturing processes to generalizations regarding subclass potential to specific case application

  41. Subclass References • Observed on consecutively made, broach-cut rifle barrels from Cooey* • Observed on consecutively made, broach-cut rifle barrels from Winchester (after absorbing Cooey)+ • Observed on groove impressions of a number of F.I.E. revolvers# *Churchman, J. The Reproduction of Characteristics in Signatures of Cooey Rifles. R.C.M.P. Gazette, 11(5), 133-140. +Skolrood, R. “Comparison of Bullets Fired From Consecutively Rifled Cooey .22 Calibre Barrels.” Canadian Society of Forensic Science Journal, 8(2), 1975, 49-52. #Lomoro, V. “Class Characteristics of 32 SWL, F.I.E. Titanic Revolvers.” AFTE Journal, 6(2), 18-21.

  42. Subclass References • Consecutively button-rifled barrels did not demonstrate subclass carry-over from one barrel to the next* • Potential for subclass characteristics (rare in any event) directly related to manufacturing process+ *Murdock, J. “A General Discussion of Gun Barrel Individuality and an Empirical Assessment of the Individuality of Consecutively Button Rifled .22 Caliber Rifle Barrels.” AFTE Journal, 13(3), 84-111. +Biasotti, A. “Rifling Methods – A Review and Assessment of the Individual Characteristics Produced.” AFTE Journal, 13(3), 34-61

  43. Subclass References • While limited subclass existed for three barrels manufactured from one button rifled blank, they did not preclude correct identification of bullets to the barrel from which they were fired* • Previously examined broach-cut barrels examined afresh – subclass transferred from only some barrels to only some groove impressions on lead bullets, copper jacketed bullets did not display any subclass characteristics from the barrels+ *Matty, W. “A Comparison of Three Individual Barrels Produced From One Button Rifled Barrel Blank.” AFTE Journal, 17(3), 64-69. +Tulleners, F. and Hamiel, J. “Sub Class Characteristics of Sequentially Rifled .38 Special S&W Revolver Barrels.” AFTE Journal, 31(2), 117.

  44. Subclass References • Lathe turned firing pins produced remarkably similar concentric circles causing examiners to look for other markings within the firing pin* *Matty, W. and Johnson, T. “A Comparison of Manufacturing Marks on Smith & Wesson Firing Pins.” AFTE Journal, 16(3), 51-56.

  45. Subclass References • Cut, stamped, and milled breech faces can all result in subclass causing examiners to look at other features within the breech face markings* *Lardizabal, P. “Cartridge Case Study of the Heckler and Koch USP.” AFTE Journal, 27(1), 49-51; Thompson, E. “False Breech Face Id's.” AFTE Journal, 28(2), 95-96; Matty, W. “Lorcin L9MM and L380 Pistol Breechface Tool Mark Patterns.” AFTE Journal, 31(2), 134-137; Lopez, L. and Grew, S. “Consecutively Machined Ruger Bolt Faces.” AFTE Journal, 32(1), 19-24.

  46. Subclass References • CNC (Computer Numerical Controlled) Machining • Consecutively manufactured Ruger bolt faces demonstrated subclass yet significant individual features to permit identification* • Consecutively manufactured .22 caliber barrels with subclass on the breech ends causing carryover of characteristics in anvil marks+ *Coffman, B. “Computer Numerical Control (CNC) Production Tooling and Repeatable Characteristics on Ten Remington Model 870 Production Run Breech Bolts.” AFTE Journal, 35(1), 49-54. +Nies, R. “Anvil Marks of the Ruger MKII Target Pistol – An Example of Subclass Characteristics.” AFTE Journal, 35(1), 75-78.

  47. Subclass References • Ten Consecutively Manufactured Extractors* • Persistent subclass on two surfaces • Despite subclass on tools, test marks did not show subclass *Nichols, R. “Firearm and Tool Mark Identification: The Scientific Reliability and Validity of the AFTE Theory of Identification Discussed Within the Framework of a Study of Ten Consecutively Manufactured Extractors.” AFTE Journal, 36(1), 67-88.

  48. Subclass References • Other Tools • Screwdrivers – could exist unless ground after stamping or die process* • Pliers – though not present from broach cut process, would have been irrelevant because direction of use perpendicular to orientation of tool marks+ *Burd, D. and Kirk, P., “Tool Marks: Factors Involved in Their Comparison and Use as Evidence,” Journal of Police Science, 32(6), 1942. +Cassidy, F. “Examination of Tool Marks from Sequentially Manufactured Tongue and Groove Pliers.” JFS, 25(4), 796-809.

  49. Subclass References • Persistence across generations – defects in molds can result in similar marks on many items* and a defect in a master mold could be reproduced in many molds which in turn…+ *Kreiser, J. “Identification of Cast Bullets and Their Molds.” AFTE Journal, 17(3), 88-90. +Miller, J. “An Introduction to the Forensic Examination of Tool Marks.” AFTE Journal, 33(3), 233-248.

  50. Rate of Change for Subclass Characteristics • The contention – “Nor have they developed statistics or generalizations about the rate(s) at which subclass characteristics on toolmarks produced by various types of tools can be expected to be replaced and/or joined by individual characteristics.”* *Schwartz, p. 9

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