Testability of the Scientific Principle

Bachrach, B., "Development of a 3D-Based Automated Firearms Evidence Comparison System", Journal of Forensic Sciences, Vol. 47(6), November 2002, pp. 1253-1264.

This study reports on a computerized system that calculates correlation coefficients for comparisons of bullet striation patterns using generated 3-D maps of bullet surfaces. Was validated using known matches (KMs) and known non-matches (KNMs), so therefore the system arrives at a conclusion of identification (or not), with an associated probability of error. Highly relevant to our work, because shows conclusively that an objective observer (a machine) detects significant visual differences between KNMs and KMs.

Biasotti, A. A., "A Statistical Study of the Individual Characteristics of Fired Bullets", Journal of Forensic Sciences, Vol. 4(1), January 1959, pp. 34-50.

Validity study in which no more than three consecutively matching striations (CMS) were found on lead bullets fired from different guns and no more than four CMS were found on jacketed bullets fired from different guns.

Brown, C., Bryant. W., "Consecutively Rifled Gun Barrels Present in Most Crime Labs", AFTE Journal, Vol. 27, No. 3, July 1995, pp. 254-258.

Study of multi-barreled derringers in which it was assumed that barrels were rifled consecutively. One set of derringer test fires showed some good correspondence in the groove impressions (gross marks), but showed little correspondence in the land impressions.

Brundage, D. J. "The Identification of Consecutively Rifled Gun Barrels", AFTE Journal, vol. 30(3), Summer, 1998, pp. 438-444.

Validation study in which ten consecutively broach rifled pistol barrels produced by Ruger were used to test the fundamental claim that qualified examiners will rarely, if ever, commit false identifications or false eliminations.  Thirty examiners were given the test nationwide and no misidentifications were made.

Bunch, S. G. "Consecutive Matching Striation Criteria: A General Critique", Journal of Forensic Sciences, vol. 45 (5), Sept. 2000, pp. 955-962.

This paper critiques the Consecutive Matching Striation (CMS) approach to toolmark identification. The author discusses the practical and theoretical weaknesses of the approach, argues that it demands a statistical/probabilistic treatment of results - such as the use of Bayesian likelihood ratios - and also suggests much additional research is needed.

Chu, et al, "Automatic Identification of Bullet Signatures Based on Consecutive Matching Striae (CMS) Criteria", Forensic Science International, 231, 2013, Pp. 137-141.

Study of fired bullet markings from ten consecutively manufactured firearm barrels by an automated 3D signature analytic method. This study used 3D topography image capture technology with acquisitions that were cross correlated to existing firearm Consecutive Matching Striae (CMS) identification criteria. Results provided a fairly objective test that demonstrated support for these firearm CMS criteria.

Chu, Tong and Song, "Validation Tests for the Congruent Matching Cells (CMC) Method Using Cartridge Cases Fired with Consecutively Manufactured Pistol Slides", AFTE Journal, Volume 45, Number 4, Fall 2013, pp. 361-366.

Study of ten consecutively manufactured slides using 3D topography technology with correlations of paired breech marking correlation cells to establish firearm identifications. Test results showed significant separation between KM and KNM distributions without any false positive or false negative identification.

DeFrance, C. S., VanArsdale, M., "Validation Study of Electrochemical Rifling", AFTE Journal, vol. 35 (1), Winter, 2003, pp. 35-37.

Validation study in which nine examiners participated in the comparison of bullets from electrochemically rifled barrels produced by Smith & Wesson.  No misidentifications were made.

Fadul, T. G., "An Empirical Study to Evaluate the Repeatability and Uniqueness of Striations/Impressions Imparted on Consecutively Manufactured Glock EBIS Gun Barrels", AFTE Journal, Volume 43, Number 1, Winter 2011, Pp. 37-44.

An empirical study of ten consecutively manufactured Glock barrels containing the Enhanced Bullet Identification System (EBIS). Study consisted of test sets sent to 238 examiners from 150 laboratories in 44 states and 9 countries that were designed to test the examiner’s ability to correctly identify fired bullets to the barrel that fired them. The results from 183 of these examiners produced an error rate of 0.4%.  This study validated the repeatability and uniqueness of striated markings in gun barrels, as well as the ability of a competent examiner to reliably identify fired bullets to the barrels that marked them.

Freeman, R. A., "Consecutively Rifled Polygon Barrels", AFTE Journal, vol.10 (2), June 1978, pp.40-42.

This study documents the comparison of bullets fired through three consecutively manufactured polygon barrels produced by H&K for the Model P9S pistol. It was found that the bullets fired from these barrels could easily be identified to the correct barrel. Additionally, these barrels possessed a fluted chamber. Marks from the fluted chambers were visible on the bullets and could also be used for identification.

Hall, E. "Bullet Markings from Consecutively Rifled Shilen DGA Barrels", AFTE Journal, vol. 15(1), Jan., 1983, pp. 33-53.

Study of consecutively button rifled polygonal style barrels.  Conclusion implies that there should be no risk of misidentification.

Hamby J. E., Brundage D. J. , Thorpe  J. W., "The Identification of Bullets Fired from 10 Consecutively Rifled 9mm Ruger Pistol Barrels: A Research Project Involving 507 Participants from 20 Countries", AFTE Journal, Volume 41, Number 2, Spring 2009, pp. 99-110.

Bullets fired from ten (10) consecutively manufactured barrels were correctly identified to the respective barrel that fired them by five hundred-seven (507) firearm examiners from twenty (20) countries. This study validates the underlying theory that: 1) there are identifiable features imparted by a gun on the surfaces of fired bullets that 2) enable a competent firearms examiner to accurately and reliably link them to the barrel that fired them.   

Intelligent Automation, Incorporated, "A Statistical Validation of the Individuality of Guns Using High Resolution Topographical Images of Bullets", National Institute of Justice Grant #2006-DN-BX-K030, October, 2010

Study of marks on fired bullets by a topography based (3D) automated system. This study continued the analysis of a previous 2005 NIJ bullet study and validated the original premise of Firearm/Toolmark ID. This study also concluded that 1) the ability to determine that a given bullet was fired from a specific barrel depends on the individual barrel itself and not only on the brand of its manufacture, and 2) the performance of the automated analysis system used in this study is not representative of that of a trained firearms examiner as humans have a remarkable ability to perform pattern matching that is difficult to be replicated in any automated system.

Lomoro, V. J., "Class Characteristics of 32 SWL, FIE Titanic Revolvers", AFTE Journal, vol. 6 (2), 1974, pp. 18-21.

This paper points out the pitfalls of basing an identification on the groove impressions on bullets fired from F.I.E. Titanic Revolvers.  Bullets from three different guns were shown to have agreement in the groove impressions, but were found to differ significantly in the land impressions.

Lutz, M., "Consecutive Revolver Barrels", AFTE Newsletter #9, Aug., 1970, pp.24-28.

Reported results of the comparison of jacketed and lead bullets fired from two consecutively rifled barrels and that the markings on the bullets were identifiable and unique to the barrel that fired them.

Matty, W., "A Comparison of Three Individual Barrels Produced from One Button-Rifled Barrel Blank", AFTE Journal, vol. 17(3), July, 1985, pp. 64-69.

Study of the uniqueness of marks produced on bullets fired from three barrels that were produced from the same rifled barrel blank.  Subclass characteristics noted in the groove impressions, but not in the land impressions.  Study also notes that over the first few firings that the striations on the bullets change significantly.

Miller, J., "An Examination of Two Consecutively Rifled Barrels and a Review of the Literature", AFTE Journal, vol. 32 (3), Summer, 2000, pp.259-270.

Study in which bullets were pushed through two consecutively broached .44 caliber barrels and were examined using Biasotti/Murdock conservative CMS criteria for identifications.  No misidentifications.

Miller, J., "Criteria for Identification of Toolmarks, Part II: Single Land Impression Comparisons", AFTE Journal, vol. 32 (2), Spring, 2000, pp. 116-131.

This study compares bullets fired by Raven 25 Auto, Lorcin 380 Auto, and Stallard Arms 9mm pistols to specimens in the NIBIN database.  This study supports the Biasotti/Murdock conservative criteria.  

Miller, J., "An Examination of the Application of the Conservative Criteria for Identification of Striated Toolmarks Using Bullets Fired from Ten Consecutively Rifled Barrels", AFTE Journal, vol. 33 (2), Spring, 2001, pp. 125-132.

Using the bullets from the Brundage Ruger ten barrel test the author 1) identified some very minor subclass characteristics but not sufficient to cause a misidentification 2) applied the conservative CMS criteria which resulted in no misidentifications.

Miller, J., McLean M., "Criteria for Identification of Toolmarks", AFTE Journal, vol. 30 (1), 1998, pp.15-61.

Using IBIS, the authors compared land impressions of .38 Special jacketed bullets fired from S&W revolvers.  Found no CMS counts greater than six (6) for KNMs, using the computer monitor. Using a separate set of testfires and the comparison microscope, no CMS counts greater than four (4) for KNMs were found.

Murdock, J. E., "A General Discussion of Gun Barrel Individuality and an Empirical Assessment of the Individuality of Consecutively Button Rifled .22 Caliber Rifle Barrels", AFTE Journal, vol. 13 (3), 1981, pp. 84-95.

This study discusses rifling methods, including the "new", method of button rifling.  Examination of nine barrels (three consecutively rifled barrels from three manufacturers) and test fired bullets from each indicated no subclass characteristics.  First two bullets fired from each barrel could not be identified to each other which is indicative of rapid change in barrel interior, which in turn confirms individuality of barrels.

Skolrood, R. W., "Comparison of Bullets fired from Consecutively Rifled Cooey .22 calibre Barrels", Canadian Society of Forensic Science, vol. 8(2), 1975, pp. 49-52.

This paper discusses the potential for broaches to produce reproducible gross marks and that examiners should be wary of these gross marks.

Smith, E., "Cartridge Case and Bullet Comparison Validation Study with Firearms Submitted in Casework", AFTE Journal, vol. 37 (2), Spring 2005, pp. 130-135.

This validation study was designed to test the accuracy of examinations by trained firearms examiners who use pattern recognition as a method for identification.  Eight FBI examiners took the test which consisted of both bullets and cartridge cases.  No false positives or false negatives were reported.

Smith, T.P., et al., "A Validation Study of Bullet and Cartridge Case Comparisons Using Samples Representative of Actual Casework”, Journal of Forensic Sciences, Volume 61, #4, July 2016, pp. 939-946.

Using a double-blind format, this comparative analysis study was designed to represent actual casework by way of examinations and conclusions performed on sets of ammunition components minus potential source firearms.  Sets of ammunition components were randomly numbered and randomly selected to create variability in each test packet. Examiner experience ranged from three years to forty-six years, and included thirty one participants from twenty-two laboratories.  Summary statistics from cartridge case examinations revealed a false-positive error rate of 0.144% and a false-negative rate of 0.433%.  Summary statistics from bullet examinations revealed a false-positive error rate of 0.0% and a false-negative rate of 0.105%.  The study’s overall error rate was 0.303%, with an overall sensitivity of 85.2%, and an overall specificity of 86.8%.  The results of this study are presented as a realistic assessment of a trained firearm examiner’s ability to reach conclusions of identification and exclusion.

Tulleners, F., Guisto M., "Striae Reproducibility on Sectional Cuts of One Thompson Contender Barrel", AFTE Journal, vol. 30(1), 1998, pp. 62-81.

For this study, a Thompson Center Contender button rifled barrel was sectioned one inch at a time after each test firing.  A total of six sections were removed from the barrel.  Each sections bullets were compared each other to see how much the CMS count had changed.  Striae on the bullets were found to be significantly altered from one barrel section to the next.  The results obtained from adjacent barrel sections were apparently comparable to the results Biasotti obtained from different, uncut barrels.

Tulleners, F., Hamiel J., "Sub Class Characteristics of Sequentially Rifled .38 Special S&W Revolver Barrels", AFTE Journal, vol. 31 (2), 1999, pp. 117-222.

This article discusses the potential for sub-class characteristics in S&W revolver barrels.  The article points out that, examiners should be careful when examining the groove impressions on fired bullets from broach rifled barrels.

Hamby, J., Norris, S., and Petraco, N., "Evaluation of GLOCK 9 mm Firing Pin Aperture Shear Mark Individuality Based on 1,632 Different Pistols by Traditional Pattern Matching and IBIS Pattern Recognition”, Journal of Forensic Science, Volume 61, #1, January 2016, pp. 170-176.

Expanded cartridge case comparison study, combining previous research (see Hamby and Thorpe, 2009) with newly examined cartridge cases, involving a total of 1,632 different 9 mm Glock pistols.  There were no misidentifications with use of conventional pattern comparison (optical microscopy) nor with electronic imaging technology.  These empirical findings were used to establish a Bayesian probability model, estimating that the random chance of two different Glock 9mm pistols creating the same aperture shear mark is less than .0001%.  These results further validate the premise of individualization and support the hypothetical proposition that a competent firearm and toolmark examiner can correctly distinguish the firearm that fired an ammunition component.

Baldwin, D.P., Bajic, S.J., Morris, M., and Zamrow, D., "A Study of False-Positive and False-Negative Error Rates in Cartridge Case Comparisons", Ames Laboratory, USDOE Technical Report #IS-5207, April 7, 2014.

Conducted empirical study on fired cartridge cases designed to measure individual examiner false identifications and false eliminations when comparing an unknown specimen to a collection of three known fired cartridge cases. These comparison results were not subjected to respective laboratory QA verification or peer review processes. Two hundred eighteen (218) firearm examiners, the majority of whom who were AFTE members or worked at accredited forensic laboratories, responded to this study with the following results using a 95% confidence interval:

False Positives= 1.01% (Note: 20 of 22 false identifications were made by the same five examiners)
False negatives= 0.367% (Note: 2 of 4 false negatives were made by a single examiner; 215 of 218 examiners made no false elimination calls)
Maximum Likelihood Estimator= 0.939%.

Results reflect averaged error rates of individual participants, and did not include QA/QC checks employed by many laboratories that may have reduced published error rates. The study revealed that the majority of participating examiners did not make false identification or elimination calls. Inconclusive results were not treated as errors.

Bunch, S. G., Murphy D., "A Comprehensive Validity Study for the Forensic Examination of Cartridge Cases", AFTE Journal, vol. 35 (2), Spring 2003, pp. 201-203.

This validity study used 10 consecutively manufactured Glock slides to test the proposition that qualified examiners rarely or never commit false positive or false negative errors in cartridge cased exams.  FBI examiners participated in this blind study.  False positive and false negative rates were 0%.

Coffman, B. C., " Computer Numerical Control (CNC) Production Tooling and Repeatable Characteristics on Ten Remington Model 870 Production Run Breech Bolts", AFTE Journal, Volume 35, Number 1, Winter 2003, pp. 49-54.

Ten shotgun bolt faces, consecutively produced by the same CNC manufacturing machine tool, were examined and compared for the presence subclass and individual characteristics. Results of these comparisons found that the manufacturing process used to fabricate these bolts produced subclass characteristics and sufficient individual characteristics to provide uniqueness.

Coody, A. C., "Consecutively Manufactured Ruger P-89 Slides", AFTE Journal, Volume 35, Number 2, Spring 2003, pp. 157-160.

Ten consecutively produced pistol slide breechfaces were examined and compared for the presence subclass and individual characteristics. Results of these comparisons found that the manufacturing processes used to fabricate these breechfaces produced subclass characteristics and sufficient individual characteristics to provide uniqueness. 

Fadul, et al, "An Empirical Study to Improve the Scientific Foundation of Forensic Firearm and Tool Mark Identification Utilizing Ten (10) Consecutively Manufactured Slides", AFTE Journal, Volume 45, Number 4, Fall 2013, pp. 376-389.  Reprint- See next citation for original publication.

Empirical study of marks produced from 10 consecutively Ruger brand manufactured pistol slides by 217 firearm examiners from 46 states and the District of Columbia. Results of this study established an error rate of less than 0.1%, and validated toolmark durability as these slides maintained their individual signature after multiple firings.  

Fadul, T. G., et al, "An Empirical Study to Evaluate the Repeatability and Uniqueness of Striations / Impressions in Fired Cartridge Casings Fired in 10 Consecutively Manufactured Slides", National Institute of Justice, Office of Justice Programs, US Department of Justice Project Award No. 2009-DN-BX-K230.

Empirical study designed to improve the understanding of the accuracy, reliability, and measurement validity in the firearms and toolmark discipline of forensic science.

158 test sets of cartridge cases fired in ten consecutively made Ruger slides were distributed to 281 examiners in 46 states including the District of Columbia. The test sets were designed to determine an examiner"˜s ability to correctly identify the source of the fired cartridge cases.

217 examiners participated in this study and their results in this empirical study established an error rate of less than 0.1%. 

Gouwe J., Hamby J. E., Norris, S., "Comparison of 10,000 Consecutively Fired Cartridge Cases from a Model 22 Glock .40 S&W Caliber Semiautomatic Pistol", AFTE Journal, Volume 40, Number 1, Winter 2008, pp. 57-63.

Ten thousand (10,000) .40 S&W caliber cartridge cases fired from a Glock, model 22, pistol were compared. All 10,000 fired cases could be identified to each other. This study validates previous durability studies that showed identifiable markings from a tool could persist for a long period of time. 

Grooss, K. D., "The 'Hammer-Murderer'", AFTE Journal, vol. 27 (1), 1995, pp. 27-30.

An actual murder case in Germany that in effect comprised a blind test of both examiner skill and theoretical validity for cartridge case comparisons. A police officer was suspected of murder, but the lack of clues led to all Walther P5 pistols issued to police in Germany being test fired and compared to the evidence cartridge cases at the BKA lab. An identification occurred with a test-fired cartridge case from the 3704th pistol. Almost simultaneous events elsewhere proved this conclusion to be accurate. No false identifications occurred.

Hamby J., and Thorpe J., "The Examination, Evaluation and Identification of 9mm Cartridge Cases Fired from 617 Different GLOCK Model 17 & 10 Semiautomatic Pistols", AFTE Journal, Volume 41(4), Fall 2009, Pp. 310-324.

Study of cartridge cases fired from 617 different Glock pistols were conducted utilizing conventional comparative optical microscopy and electronic imaging technology to test the premise of individualization in FA/TM ID. Results of this study validated not only the premise of individualization but also the hypothetical proposition that a competent firearm and toolmark examiner can correctly identify the firearm that fired an ammunition component without committing a misidentification.

Kennington, R., "Identification of Cartridge Cases Fired in Different Firearms: "Pre-Identified Cartridges"",  AFTE Journal, vol. 31(1), 1999, pp. 15-19.

This research discusses the pitfall that toolmarks produced during the manufacturing process of ammunition components pose and that one should be mindful that these marks exist. 

LaPorte, D., "An Empirical Validation Study of Breechface Marks on .380 ACP Caliber Cartridge Cases Fired from Ten Consecutively Finished Hi-Point Model C9 Pistols", AFTE Journal, Volume 43, Number 4, Fall 2011.

Empirical and validation studies of ten consecutively manufactured Hi-Point pistol breechfaces determined that the manufacturing process imparted individual characteristics that enable a competent firearms examiner to reliably identify a questioned cartridge case to the firearm in which it was fired.    

Lardizabal, P., "Cartridge Case Study of the HK USP", AFTE Journal, vol. 27 (1), Jan., 1995, pp. 49-51.

This study examined two consecutively manufactured H&K 40 S&W caliber USP breechfaces along.  Subclass characteristics were identified on the breechface impressions.  Test fired bullets from three H&K barrels were also examined and little correspondence was found between signatures from bullets fired from different barrels. 

Lopez, L., Grew S., "Consecutively Machined Ruger Bolt Faces", AFTE Journal, vol. 32 (1), 2000, pp. 19-24.

This study warns that one should be careful with microscopic marks from a boltface machined with an end mill. Misidentification possible unless ID on wear or machining "chatter" marks.

Lyons, D. J., "The Identification of Consecutively Manufactured Extractors", AFTE Journal, Volume 41, Number 3, Summer, 2009, pp.246-256.

Study conducted on ten consecutively manufactured firearm extractors. Firearm and toolmark examiners from different laboratories were given ten sets of cartridge cases marked by these extractors to attempt to make the correct associations between the known and unknown cases. Each examiner also received twelve unknown marked cases in addition to the standards for the ten consecutively manufactured cartridge cases, with each known specimen having at least one unknown specimen associated with it.

Study showed that extractors could be distinguished from each other despite that they were consecutively manufactured.

Matty, W., "Raven .25 Automatic Pistol Breech Face Tool Marks", AFTE Journal, vol. 16 (3), 1984, pp. 57-60.

For this study, three consecutively made breechfaces from Raven pistols were compared.  The concentric toolmarks on the breechfaces were found to be individual and not subclass.

Matty, W., Johnson T., "A Comparison of Manufacturing Marks on Smith & Wesson Firing Pins", AFTE Journal vol. 16 (3), 1984, pp. 51-56.

This study examined the concentric marks produced by Smith & Wesson firing pins.  Subclass characteristics were found.  These subclass marks are a result of the lathe mounted cutter being much harder than the firing pins and thus marks can be reproduced; however, using the areas of the firing pins that show wear can be used for identification. 

Mayland and Tucker, "Validation of Obturation Marks in consecutively Reamed Chambers", AFTE Journal, Volume 44, No. 2, Spring, 2012, pp.167-169.

Study of fired cartridge cases from ten consecutively manufactured firearms was conducted to determine the reproducibility and reliability of obturation marks from reamed chambers for identification purposes. Results of this empirical study, which consisted of sixty-four (64) participants from nineteen (19) national laboratory systems, effected a sensitivity rating of 0.927.

These results demonstrate that obturation markings imparted on fired cartridge cases can be used as a reliable means of identification to the firearm that marked them.

Petraco D. K., et al, "Application of Machine Learning to Toolmarks: Statistically Based Methods for Impression Pattern Comparisons", NIJ/NCJRS Document #239048, Award #2009-DN-BX-K041, July 2012

Statistical study using 3D quantitative surface topographies of toolmarks, consisting of fired cartridge cases, screwdriver and chisel striations, by confocal microscopy. Principal component and canonical variate analysis, as well as support vector machine methodology, was used to objectively associate these toolmarks with the tools that produced them. Estimated toolmark identification error rates were approximately 1% using these algorithmic methods. The findings of this objective and quantitative scientific research support the general conclusions codified in the AFTE Theory of Identification.

Rosati, C., "Examination of Four Consecutively Manufactured Bunter Tools", AFTE Journal, vol. 32 (1), 2000, pp. 49-50.

For this study, four bunters produced by Electrical Discharge Machining (EDM) used by Remington for .45 Auto cartridge case manufacture were used to determine if this process was random in nature. Confirms random nature of marks from EDM process on headstamp characters.

Saribey, A. Y., Hannam A. G., Tarimci C., "An Investigation into Whether or Not the Class and Individual Characteristics of Five Turkish Manufactured Pistols Change During Extensive Firing", Journal of Forensic Sciences, Volume 54, Number (5), September 2009, Pp.1068-1072.

Conducted statistical durability study of fired cartridge cases from five different pistols. Each pistol had at least 1000 cartridge cases fired in them with every 250th case compared to the first fired case. Although there were noted changes in individual and some class characteristics, these wear changes were not statistically significant based on standard deviation measurements. This study statistically validated previous durability studies.

Smith, T.P., et al., "A Validation Study of Bullet and Cartridge Case Comparisons Using Samples Representative of Actual Casework”, Journal of Forensic Sciences, Volume 61, #4, July 2016, pp. 939-946.

Using a double-blind format, this comparative analysis study was designed to represent actual casework by way of examinations and conclusions performed on sets of ammunition components minus potential source firearms.  Sets of ammunition components were randomly numbered and randomly selected to create variability in each test packet. Examiner experience ranged from three years to forty-six years, and included thirty one participants from twenty-two laboratories.  Summary statistics from cartridge case examinations revealed a false-positive error rate of 0.144% and a false-negative rate of 0.433%.  Summary statistics from bullet examinations revealed a false-positive error rate of 0.0% and a false-negative rate of 0.105%.  The study’s overall error rate was 0.303%, with an overall sensitivity of 85.2%, and an overall specificity of 86.8%.  The results of this study are presented as a realistic assessment of a trained firearm examiner’s ability to reach conclusions of identification and exclusion.

Stroman, A., "Empirically Determined Frequency of Error in Cartridge Case Examinations Using a Declared Double-Blind Format", AFTE Journal, Vol. 46, No. 2, Spring 2014, Pp. 157-175.

No gun empirical study of fired cartridge cases to determine the frequency of error in firearms identification using a declared double-blind testing format; i.e., a declared test containing blind elements. Seventy-four of seventy-five examiners accurately identified the questioned fired cartridge cases to the respective known specimens with no false positives. This study also demonstrated that examiners were able to accurately evaluate breechface markings avoiding mis-identifications from substantial subclass marks contained cartridge cases. 

Thompson, E., "Phoenix Arms (Raven) Breechface Toolmarks", AFTE Journal, vol. 26 (2), 1994, pp. 134-135.

This is a follow-up study of the Matty article on Raven breechfaces.  Four breechfaces from Phoenix pistols (formerly Raven) were compared to determine the nature of their marks.  As in the Matty article the breechfaces were found to possess unique identifying marks.

Thompson, E., "False Breechface ID's", AFTE Journal, vol. 28 (2), April, 1996, pp. 95-96.

This study examines the manufacturing process of Lorcin pistol breechfaces.  Of noteworthiness is the fact that Lorcin breechfaces are stamped and then painted over not machined.  False identifications could be possible if the only marks considered are from the breechface. Also noted was the fact that paint on breechfaces has a tendency to chip off and that one should not solely rely on the breechface impression as a means for identification.

Thompson, R., Song J., Zheng A., and Yen J.  "Cartridge Case Signature Identification Using Topography Measurements and Correlations: Unification of Microscopy and Objective Statistical Methods", National Institute of Standards and Technology, Presented at the 18th European Network of Forensic Science Institutes (ENFSI) Conference, Lisbon, Portugal, October, 2011

A comparison microscope employing the standard optical comparison method and confocal microscopy, with subsequent cross correlation topography analysis, were used to correctly identify cartridge cases fired from ten consecutively made pistol slides.

Subsequent cross correlation function analysis and statistical analysis of match and non-match scores correctly identified the fired cartridge cases back to their respective known slide source in 19 of 20 occasions with one inconclusive result. Results of the mathematical determination of slide source were compared to the validated results from the microscopic comparisons.

Uchiyama, T., "Similarity among Breech Face Marks Fired from Guns with Close Serial Numbers", AFTE Journal, vol. 18 (3), 1986, pp. 15-52.

This study examined the breechface marks produced by Browning Baby, Raven P-25 and Titan pistols.  Subclass characteristic were found to be significant on the breechface of each of these pistol models and examiners should use caution when encountered.

Weller, T. J., et al, "Confocal Microscopy Analysis of Breech Face Marks on Fired Cartridge Cases from 10 Consecutively Manufactured Pistol Slides", Journal of Forensic Sciences, Volume 57, Number 4, July 2012, pp. 912-917.

Microscopic study of 90 test fired cartridge case specimens from ten consecutively manufactured pistol slides. A total of 8010 comparisons were conducted by using confocal microscopy with a 3D cross-correlation analysis logarithm. The average match scores were 0.82 with the average non-match scores 0.20. There was no overlap of scores between matching and non-matching test scores. This study provided objective data that supports the AFTE Theory of Identification. 

Brackett, J. W. "A Study of Idealized Striated Marks and their Comparisons using Models", Journal of the Forensic Science Society, vol. 10 (1), January, 1970, pp. 27-56.

Comparison of various proposed probability models for striated marks, with an eye toward the development of an automated system. CMS model tended to support empirical work of Biasotti.

Collins, E. R., "How Unique Are Impressed Toolmarks? An Empirical Study of 20 Worn Hammer Faces", AFTE Journal, vol. 37 (4), Fall 2005, pp. 252-295.

This study utilizes 20 worn hammer faces to determine if Stone’s (2003) theoretical types of toolmark characteristics model "accurately and consistently represents the occurrence of individualizing effects", This study includes an addendum by Stone which outlines refinements to his original model. The refinements to the original model continue to provide probabilities that are astronomical.

Deinet, W., "Studies of Models of Striated Marks Generated by Random Processes", Journal of Forensic Sciences, vol. 26 (1), Jan., 1981, pp. 35-50.

Computer-aided studies of the degree of similarity of striated marks are described. Digitized image data on 40 grinding marks were fed into a minicomputer, and the position values of the lines were determined semiautomatically. Idealized models were defined for an objective comparison of striated marks and then applied to the grinding mark data. Necessary conditions of the models were tested by comparing them with actual, measured properties of the marks. Results of the model calculations are presented and the properties of the models discussed.

Hatcher, J. S., Jury, F. J., Weller, J., "Firearm Investigation Identification and Evidence", The Stackpole Company, 1957 P. 389 P.380

Calculated, in a restricted example, that the possibility of the same set of identifiable marks appearing on another tool is approximately 1 in 432,000,000,000 (trillion).

Heard, B. J., "Handbook of Firearms and Ballistics", Wiley & Sons, 1997, pp. 136-141

Calculated, in a restricted example, that the possibility of the same mark(s) appearing on another tool is approximately 1 in 52,860,000,000 (billion).

Howitt D., Tulleners F., "A Calculation of the Theoretical Significance of Matched Bullets", Journal of Forensic Sciences, Volume 53, Number 4, July 2008, Pp.868-875.

Study that calculated random occurrence probability for the correspondence of impression marks on a subject bullet to a random distribution of similar marks on a suspect bullet of the same type. These calculations produced values that supported previous reported empirical probabilities on consecutive matching bullet striae and also indicate that larger consecutive matching sequences are extremely unlikely to occur.

May L., "Identification of Knives, Tools and Instruments", Journal of Police Science (no volume or number listed) 1930, pp. 247-248.

Conducted pioneering study on striated type toolmarks on numerous cutting tools, especially knives, with working edges containing some type of grinded finish.

Also, conducted first attempt at a statistical validation in Toolmark Identification; in which, it was calculated that the possibility of the same identifying mark(s) appearing on another tool is approximately 100,000 X 650 quadrillion.

Neel M., and Wells M., "A Comprehensive Statistical Analysis of Striated Tool Mark Examinations Part I: Comparing Known Matches and Known Non-Matches", AFTE Journal, Volume 39, (4), Summer 2007, pp. 176-198.

Study of 4000 striated toolmark comparisons concluded that known matches (KM) and known non-matches (KNM’s) can be statistically distinguished from one another with 3D toolmarks containing a 1 in 802,919 and 2D toolmarks containing a 1 in 12,090,164 likelihood ratio.

Petraco, D. K., et al, "Addressing the National Academy of Sciences Challenge: A Method for Statistical Pattern Comparison of Striated Tool Marks", Journal of Forensic Sciences, Volume 57, Number 4, July 2012, pp. 900-911.

Toolmark test specimens from nine slotted screwdrivers were encoded into high-dimensional feature vectors and analyzed by multiple statistical pattern recognition methods. The statistical methods used, which are widely known and accepted in academic applications, rely on few assumptions of the data"™s underlying distribution, can be accompanied by standard confidence levels and are falsifiable. Correct classification rates of at least 97% were achieved.

Stone, Rocky, "How Unique are Impressed Marks", AFTE Journal, vol. 35 (4), Fall 2003, pp. 376-383.

This study outlines several theoretical types of impressed toolmark characteristics (point, line, curve, enclosure and three-dimensional) and applies mathematical probability estimates in an attempt to quantify them. It was found that marks of "reasonable complexity", that the odds of the same marks being repeated on another tool to be astronomical.

Macziewski, C., Spotts, R., and Chumbley, S., "Validation of Toolmark Comparisons Made at Different Vertical and Horizontal Angles”, Journal of Forensic Sciences, Volume 62, #3, May 2017, pp. 612-618.

Another installment in a series of toolmark studies conducted by Chumbley, et al. An algorithm previously used to separate matching and non-matching striated toolmarks was used to compare striated toolmarks made by a set of ten consecutively manufactured screwdriver tips. Each tip was used to make a series of toolmarks at predetermined vertical and horizontal (twist) angles.  The algorithm was used to compare toolmark data files created by way of focus variation microscope scans.  The algorithm was able to distinguish known matches vs. non-matches when toolmarks were made at the same or similar angles, but this ability diminished significantly when comparisons involved horizontal (twist) angle differences greater than 10 degrees (the foreshortening effect).  Despite a lack of complete statistical separation, authors found that there were statistically higher correlations between known matching toolmarks (even when comparing marks at vastly different vertical and horizontal angles) than seen in known non-matching toolmarks.  Results support the basic assumption that each tool possesses distinctive characteristics that separate it from other tools.

Spotts, R., Chumbley, L.S., "Objective Analysis of Impressed Chisel Toolmarks”, Journal of Forensic Science, Volume 60, #6, November 2015, pp. 1436-1440.

Continuation of a series of toolmark studies conducted by Chumbley, et al. An algorithm previously used to separate matching and non-matching striated toolmarks was used on impressed toolmarks made by fifty sequentially manufactured chisels.  This study was a more difficult test of the algorithm, as the algorithm was not designed for analysis of complex impression toolmarks.  Results showed that the algorithm is capable of separating matching and non-matching impressed toolmarks, providing further validation of the assumption that toolmarks are “identifiably unique.”

Spotts, R., et al, "Optimization of a Statistical Algorithm for Objective Comparison of Toolmarks", Journal of Forensic Science, Volume 60, #2, March 2015, pp. 303-314.

Continuation of a series of toolmark studies conducted by Zhang and Chumbley, and Ekstrand, et al. This particular study utilized an algorithm to separate matching and non-matching toolmarks created by fifty sequentially manufactured shearing tools. Results showed a high degree of statistical separation between matching and non-matching tool distributions. This study provides further validation of the distinguishing capabilities of toolmarks and their identifying capabilities as promulgated in the theory of Toolmark Identification.

Petraco, N.D.K., et al, "Estimation of Striation Pattern Identification Error Rates by Algorithmic Methods", AFTE Journal, Volume 45, #3, Summer 2013, Pp. 235-244.

Computational study using algorithmic methods of toolmark striation patterns produced by screwdriver tips and firearm firing pin apertures in determining error rates. Multivariate analysis, as well as support vector machine methodology, was used to objectively associate these toolmarks with the tools that produced them. Estimated toolmark identification error rates were approximately 1% using these algorithmic methods. The findings of this objective and quantitative scientific research support the general conclusions codified in the AFTE Theory of Identification.

Bachrach B., Jain A., Jung S., Koons R.D., "A Statistical Validation of the Individuality and Repeatability of Striate Tool Marks: Screwdrivers and Tongue and Groove Pliers", Journal of Forensic Sciences, Volume 55, Number 2, March 2010, Pp 348-357.

Study that statistically validated the original premise of individuality in Toolmark Identification by analyzing statistical distributions of similar values resulting from the comparison of Known Matches (KM) and Known Non-Matched (KNM) pairs of striated toolmarks. This quantifiable analysis of KM and KNM toolmark similarity distributions showed nearly error-free identifications.

Bacharach, B., "Statistical Validation on the Individuality of Tool Marks Due to the Effect of Wear, Environment Exposure and Partial Evidence", NIJ/NCJRS Document #227929, August, 2009.

An objective, quantifiable toolmark study on marks imparted onto wires by diagonal cutters. This study examined the effects of wear, environmental conditions and partial toolmark impressions by an automated 3-D system that mathematically correlated results of toolmarks to the tools that produced them. This study validated and, thus, strengthened the foundations of Toolmark Identification.

Burd, David Q., Gilmore A. E., "Individual and Class Characteristics of Tools", Journal of Forensic Sciences, vol. 13 (3), July, 1968, pp. 390-396.

This article discusses tools made from molds, such as die stamps and die forgings and the possibility of confusing class marks as individual marks. 

Butcher, S., Pugh D., "A Study of Marks made by Bolt Cutters", Journal of the Forensic Science Society, vol. 15 (2), Apr., 1975, pp. 115-126.

This study examines test marks made by ten consecutively made bolt cutters and ten randomly selected bolt cutters with ground working surfaces.  The study determined that no more than 29% matching stria for known non-matches and between 87% and 93% matching stria for known matches. Implication: no risk of misidentification.

Cassidy, F., "Examination of Toolmarks from Sequentially Manufactured Tongue and Groove Pliers", Journal of Forensic Sciences, vol. 25 (4), Oct., 1980, pp. 796-809.

This study examines the individuality of striated marks produced by consecutively broach cut tongue and groove pliers.  Examination of the jaw teeth and their test marks revealed no subclass marks and that the striated marks produced are individual to the tool that made them.

Chumbly, L. S., et al, "Validation of Tool Mark Comparisons Obtained Using a Quantitative, Comparative, Statistical Algorithm", Journal of Forensic Sciences, Volume 55, Number 4, July 2010, Pp. 953-961.

A statistical analysis and computational algorithm for comparing pairs of toolmarks by profilometry data was conducted. Toolmarks produced by 50 sequentially made screwdrivers, at selected fixed angles, were analyzed both empirically by practicing examiners and by the established computational algorithms. The results of these comparisons, as well as a subsequent blind study with the practicing examiners, showed scores of good agreement between the algorithm and human experts. It was also noted that in some of the examination phases, examiner performance was much better than the algorithm.

Clow, C. M., "Cartilage Stabbing with Consecutively Manufactured Knives: A Response to Ramirez v. State of Florida", AFTE Journal, vol. 37 (2), Spring, 2005, pp. 86-116.

This study utilized ten consecutively manufactured knives used in a stabbing motion to determine if the marks produced were unique and if marks were reproducible and identifiable in pig cartilage.  Marks were found to be unique.  Marks reproduced and were found to be potentially identifiable in cartilage.

Eckerman, S. J., "A Study of Consecutively Manufactured Chisels", AFTE Journal, vol. 34 (4), Fall 2002, pp. 379-390.

In this study, consecutively belt sanded chisels were examined for the possibility of subclass marks.  The marks were found to be individual to each chisel.

Ekstrand, et al, "Virtual Tool Mark Generation for Efficient Striation Analysis", Journal of Forensic Sciences, Volume 59, #4, July 2014, Pp. 950-959.

Follow-up study on Zhang and Chumbley"™s research (See Emerging Research Section) regarding the development of virtual toolmarks by a 3-D computer simulation that would allow for the development of highly predictable toolmark characterizations. Initial study involved the production of test toolmarks by six screwdriver tips that were then compared by a previously developed statistical algorithm. 

Preliminary experimental results indicate that the use of a manipulative, virtual tool could provide quantitative data for the characterization of tool marked surfaces that would improve the scientific basis of toolmark identification. These results support the present theory and conclusions held in Toolmark Identification. 

Flynn, E. M., "Toolmark Identification", Journal of Forensic Sciences, vol. 2 (1), Jan., 1957, pp.95-106.

In this study, Chicago Police Crime Lab examined 100 consecutively made chisels finished with a grinding process. 5050 total comparisons made. No misidentifications.

Giroux B. N., "Empirical and Validity Study: Consecutively Manufactured Screwdrivers", AFTE Journal, Volume 41, Number 2, Spring 2009, pp. 153-158.

The fundamental propositions of Toolmark Identification were tested with an empirical and validation study of five consecutively manufactured screwdrivers. The empirical study compared the machining marks imparted on the working surfaces of these screwdrivers to toolmark specimens produced by these screwdrivers. Eight qualified examiners at the FBI Laboratory participated in a blind validation study where eighty comparisons were conducted on the toolmarks produced by these screwdrivers. The results of this blind validity study effected no mis-identifications and one mis-elimination.

Hall, J., "Consecutive cuts made by bolt cutters and their effect on identification", AFTE Journal, vol. 24 (3), July, 1992, pp. 260-272.

This study showed consecutive cuts in lead with bolt cutters are identifiable showing that lead is a suitable material for test marks.  Cuts in shackles may or may not change the tool  depending upon the hardness of the shackle.

Hornsby, B., "MCC Bolt Cutters", AFTE Journal, vol. 21 (3), July, 1989, p. 508.

This study randomly selected bolt cutters from the same production run.  The working surfaces of the bolt cutters were produced through milling and tumbling.  The study concluded that marks produced by bolt cutters were unique to the tool that made them.  

Jordan, T., "Individual Characteristics on Copper Insulated Wire", AFTE Journal, vol. 14 (1), 1982, pp. 53-56.

Using 3 to 6 inch sections of #12 insulated copper wire, this study revealed that the drawing marks are unique to the tool that produced them.

Lee, S. E., "Examination of Consecutively Manufactured Slotted Screwdrivers", AFTE Journal, vol. 35 (1), Winter,   2003, pp. 66-70.

This study used five consecutively made screwdrivers to test the reproducibility of marks produced at various angles with both pushing and pulling motions.  Each screwdriver"™s marks were found to be individual to tool that produced them.

Miller, J., Beach, G., "Toolmarks: Examining the Possibility of Subclass Characteristics", AFTE Journal, vol. 37 (4), Fall 2005, pp. 296-345.

This study utilizes consecutively manufactured diagonal cutting pliers, slip joint pliers, center punches, cold chisels and beveled wood chisels to determine if these tools possess subclass characteristics and individual characteristics. In all cases, except the center punches, subclass characteristics and individual characteristics were observed. The grinding process used to finish the punches produce individual characteristics only. The remaining tools produce marks that are easily identified as individual characteristics or a combination of subclass and individual characteristics which are easily discernible.

Miller, J., "Cut Nail Manufacturing and Toolmark Identification", AFTE Journal, vol. 30 (3), Summer 1998, pp. 492-498.

This study discusses the cut nail manufacturing process and a test was produced in which 32,000 + nails were identified to the tools that made them.

Murdock, J. E., "The Individuality of Tool Marks Produced by Desk Staplers", AFTE Journal, vol. 6 (5), 1974. pp. 23-39.

This study found that Pilot brand staplers produced individual marks on staples, while Swingline brand staplers produced only class marks. The manufacturers used different manufacturing methods which was the reason for the differing types of marks.

Petraco D. K., et al, "Application of Machine Learning to Toolmarks: Statistically Based Methods for Impression Pattern Comparisons", NIJ/NCJRS Document #239048, Award #2009-DN-BX-K041, July 2012

Statistical study using 3D quantitative surface topographies of toolmarks, consisting of fired cartridge cases, screwdriver and chisel striations, by confocal microscopy. Principal component and canonical variate analysis, as well as support vector machine methodology, was used to objectively associate these toolmarks with the tools that produced them. Estimated toolmark identification error rates were approximately 1% using these algorithmic methods. The findings of this objective and quantitative scientific research support the general conclusions codified in the AFTE Theory of Identification.

Reitz, J., "An Unusual Toolmark Identification Case", AFTE Journal, vol. 7 (3), Dec., 1975, pp. 40-43.

Consecutively ground and randomly selected twist drill bits were studied.  Results show no risk of misidentification.

Thompson, E. and Wyant, R., "Knife Identification Project (KIP),", AFTE Journal, vol. 35 (4), Fall 2003, pp. 366 "“ 370.

This study utilizes ten consecutively manufactured knives produced by the Benchmade Knife Corporation to produce a test to demonstrate the uniqueness of striated toolmarks. One hundred and forty tests were distributed at the 2002 AFTE Training Seminar. One hundred and three examiners submitted results for inclusion in the study. Of the possible 1,030 possible answers, 1,022 were correct (8 incorrect answers). The error rate for this study was calculated to be 0.776 percent.

Tuira, Y. J., "Tire Stabbing with Consecutively Manufactured Knives", AFTE Journal, vol. 14 (1), 1982, pp. 50-52.

Two consecutively made Buck knives were thrust into inflated tire and the toolmarks compared.  The toolmarks were found to be significantly different.

Van Dijk, T. M., "Steel Marking Stamps: Their Individuality at the Time of Manufacture", Journal of the Forensic Science Society, vol. 25 (4), July/Aug, 1985, pp. 243-253.

Fifty steel marking stamps made from the same hob (die) were examined for subclass marks. Unique defects from the hobbing process could be used to correctly identify each stamp.

Watson, D., "The Identification of Toolmarks produced from consecutively manufactured knife blades in soft plastics", AFTE Journal, vol. 10 (3), September, 1978, pp. 43-45.

This article discusses the uniqueness of two consecutively manufactured knives.  No carryover was found to exist between the two knives.  

Watson, D. J., "The Identification of Consecutively Manufactured Crimping Dies", AFTE Journal, vol. 10, September 1978, pp. 19-21.

This study documents the manufacturing process of crimping dies and the results of the comparison of two consecutively manufactured crimping dies. It was found that the crimping dies bore no "carry-over", effects and that lead seals crimped with these dies could be identified back their source.

Zheng, X.A., et al, "2D and 3D Topography Comparisons of Toolmarks Produced from Consecutively Manufactured Chisels and Punches", AFTE Journal, Vol. 46, No. 2, Spring 2014, Pp. 143-147.

Automated blind study of toolmarks from consecutively made chisel and punches utilizing 2D and 3D topography analysis, and expressing these analytical comparative results as a maximum value of the normalized Cross Correlation Function (CCF). Based on the CCF metric, all of the toolmarks were correctly identified to the tool that produced them. This study provides additional objective scientific support for the validity of Toolmark Identification. 

Christensen A. M., Sylvester A. D., "Physical Matches of Bone, Shell and Tooth Fragments: A Validation Study", J Forensic Science 2008;53:694-698

Fifty-seven fragments of human bones, nonhuman bones, nonhuman teeth, turtle shell, and mollusks shells were examined by ninety-five individuals with varying levels of education and experience.  There were 40 possible associations and 6 fragments that had no corresponding match.  The positive association rate (correct identification) was 92.5%, the non-association rate (no-conclusion) was 7.5%, and the number of negative associations (false identification) was 0.1%.

Claytor D., "Validation of Fracture Matching Trough the Microscopic Examination of the Fractured Surfaces of Hacksaw Blades", AFTE Journal, Vol. 42(4), Fall 2010, pp. 323-334. 

Validation of fracture matching method utilizing two consecutively manufactured hacksaw blades fractured eleven times and inter-compared. Two hundred fifty-three topical comparisons were conducted between forty-four fractured edges. Additional fractured hacksaw blade test specimens were produced and sent to examiners around the world yielding three hundred-thirty test results.  

Katterwe, H. W., "Fracture Matching and Repetitive Experiments: A Contribution of Validation", AFTE Journal vol. 37 (3), Summer 2005, pp. 229-241.

This study utilizes glass, polymer and metal as materials to repetitively test the uniqueness of fracture patterns. The results of these tests validate the "that the individualization of fracture surfaces is a process that relies on the scientific principles of fracture mechanics",

Miller, J., Kong, H., "Metal Fractures: Matching and Non-Matching Patterns", AFTE Journal, vol. 38 (2), Spring 2006, pp. 133-165.

This study used six different sets of key blanks. Each set of blanks was cut to fit the same lock. The keys were broken at approximately the same blade location. These items were then compared using the "jigsaw puzzle", type fit and an internal fracture pattern comparison. The findings support the conclusion that the action of breaking and fracturing produce unique patterns and can be used to provide opinions of common origin of broken objects.

Orench, J. A., "A Validation Study of Fracture Matching Metal Specimens Failed in Tension", AFTE Journal, vol. 37 (2), Spring 2005, pp. 142-149.

This study utilizes sections of 0.25 inch 1045 carbon steel that were overloaded with tension. To insure uniformity of the breaks, a diamond cutter was used to notch the midpoint of each section of steel. A MTS Tensile Tester was used to pull apart each section. A test was generated to determine if ten examiners could match the fractured steel segments back to their opposing fractured steel segment. All ten examiners correctly identified the matching segments. Additionally, the non-matching segments produced no false positives.

Riva, F. et al., "Objective Evaluation of Subclass Characteristics on Breech Face Marks”, Journal of Forensic Sciences, Vol. 62, No. 2, March 2017, pp. 417-422.

An automated 3D comparison of cartridge case marks created by thirteen Smith & Wesson Sigma-style 40 S&W caliber pistols was conducted in order to evaluate the influence of subclass characteristics.  Results showed that influence of subclass marks had a limited impact on likelihood ratios, even when subclass features were intentionally increased in the pool of potential source firearms.  These results do not predict similar outcomes involving greater numbers of firearms of different makes/models/calibers, but they do provide evidence that likelihood ratios derived from the use of 3D topographical comparisons can be informative despite the presence of subclass features.  The design of this study suggests that over 40% of firearms in a pool of potential sources would need to possess subclass features in order to significantly affect the outcome of automated comparisons.

Hare, E., Hofmann, H., and Carriquiry, A., "Automatic Matching of Bullet Land Impressions”, The Annals of Applied Statistics, Volume 11, Number 4 (2017), pp. 2332-2356.

Images and associated topographical information (the Hamby barrel study data) obtained from the NIST Ballistics Database Project were used to convert individual characteristics from bullet land impressions into a set of features that quantify individual characteristic similarities.  An algorithm was applied to this data to in order to objectively compare the similarity of land impressions on a land to land level (as opposed to a bullet to bullet level).  A total of 10,384 land impression to land impression comparisons were conducted via this method and, when using a cut-off probability of 0.5, the matching algorithm correctly predicted all known matching and known non-matching land impressions.  Parameter choices applied to the matching algorithm were found to affect results.  Additional study involving larger data sets is needed to fully test the underlying assumptions of uniqueness and reproducibility of markings transferred from firearms to bullets.

Riva, F. and Champod C., "Automatic Comparison and Evaluation of Impressions Left by a Firearm on Fired Cartridge Cases", Journal of Forensic Sciences, Vol. 59, No. 3, May 2014, Pp. 637-647.

Automated study of marks contained on fired cartridge cases from seventy-nine 9mm Luger caliber pistols were conducted using 3D surface topography analysis and coupled to a bivariate evaluative model to assign likelihood ratios. The purpose of this analytic system was to conduct an objective comparative analysis with a robust statistical evaluation basis to the results.

The system reflected a very high discriminating ability between the known and non-known specimens. This study also reflected very low rates of misleading evidence depending on the firearm considered. 

Zhang, S. and Chumbley, L.S., "Manipulative Virtual Tools for Tool Mark Characterization", NCJRS Document #241443, Award # 2009-DN-R-119, March 2013.

Research on the development of virtual toolmarks by a 3-D computer simulation that would allow for the development of highly predictable toolmark characterizations. Initial study involved the production of test toolmarks by six screwdriver tips that were then compared by a previously developed statistical algorithm.

Preliminary experimental results indicate that the use of a manipulative, virtual tool could provide quantitative data for the characterization of tool marked surfaces that would improve the scientific basis of toolmark identification.

Song, J., et al, "Development of Ballistics Identification- from Image Comparison to Topography Measurement in Surface Metrology", Measurement Science and Technology, Volume 23, Number 054010, March, 2012.

Systematic study of direct measurement and correlation of surface topography on fired bullet markings was employed. Based on this on this system, a prototype for bullet signature measurement and correlation was developed that has demonstrated superior correlation results for bullet signature identifications.  

Chu, W., et al, "Selecting Valid Correlation Areas for Automated Bullet Identification System Based on Striation Detection", Journal of Research of the National Institute of Standards and Technology, Volume 116, Number 3, May-June 2011.

Study on fired bullet markings using automated bullet identification systems that employ an edge detection algorithm and selection process that locates the edge points of significant toolmark features was conducted.  Results of this study validate the differentiation ability of individual characteristics if a proper striation threshold length can be established.