Download
1 / 41
460 likes | 783 Views
Firearm and Tool mark identification. A GENERAL PRIMER Genesee County Bar Association Criminal Law Seminar-2013. COOL, ATTRACTIVE PEOPLE. REAL LIFE. AWKWARD NERDS. CSI-BRIDGEPORT. Major Historical Events in Early Firearm and Tool Mark Identification. Brownsville Affray, 1907
E N D
Firearm and Tool mark identification A GENERAL PRIMER Genesee County Bar Association Criminal Law Seminar-2013
REAL LIFE AWKWARD NERDS CSI-BRIDGEPORT
Major Historical Events in Early Firearm and Tool Mark Identification. • Brownsville Affray, 1907 • Prof. Balthazard, 1912-Photomicrograph Comparisons • Stielow Case, 1915 • Sacco and Vanzetti Case, 1920 • Waite/Goddard Partnership: 1924-Use of the Comparison Bridge Microscope • St. Valentine’s Day Massacre of 1929 • Opening of the Chicago Crime Lab at Northwestern University in 1930 by Calvin Goddard. First ever Public Forensic Science Laboratory. • 1932: FBI Lab opens with one person, who was an agent (Charles Appel) trained at Northwestern by Calvin Goddard and co. Appel soon after handled the Lindburgh baby case as a questioned document examiner.
Scientific Studies • 1920s-1930’s: • In the U.S., the work of individuals such as Col. Calvin Goddard, J. Howard Matthews, and Maj. Julian Hatcher provide study and insight into the science supporting Firearm and Tool Mark Identification. The examination methodology is standardized in terms of Classification and Identification, and texts are popularized for use and training of Firearms Examiners. • In Europe, the work of individuals such as French Professor Victor Balthazard, Robert Churchill, Sir Gerald Burrard, and Col. H.W. Todhunter further the practice through study and the writing of subject matter. • Courts around the country (and in Europe) begin to commonly accept forensic firearm and tool mark expert testimony by the 1940’s.
Contemporary Scientific Studies • 1955: A.A. Biasotti completes his 97 page thesis concerning “Bullet Comparisons—A Study of Fired Bullets Statistically Analyzed.” • Biasotti goes on to publish several other very important statistical studies concerning striated tool marks on fired bullets throughout the 50’s, 60’s, and early 70’s. • Other examiners expand on these studies, which create statistical foundations for striated toolmarks.
Contemporary Scientific Studies • 1969: Association of Firearm and Toolmark Examiners (AFTE) is chartered. The AFTE Journal is popularized as a peer-reviewed scientific journal concerning the relevant field. • 1990’s-2000’s: Statistical studies concerning algorithmic databasing of IMC, impressed toolmarks, 3d imaging, striated toolmarks, stochastic probability, and more continue to be produced. Academia begins to again become more involved due to the prevalence of Forensic Science Programs at universities.
Battlefield Forensics • Firearm Identification is firmly lodged in wartime battlefield forensic science and intelligence. Mobile and temporary labs are staffed by USACIL (US Army Criminal Investigation Laboratory) in the middle east theatres, and USACIL has for 70 years intermittently operated several Forensic Science Laboratories in the US, the Phillippines, Japan, and Vietnam. • In the first years of the Iraq/Afghanistan wars, firearm and toolmark examiners were privately offered upwards of $250,000 tax free to work one year stints within the theatre of operations.
Identification Criteria SWGGUN and AFTE (Relevant Scientific Community)
2.2 • SWGGUN endorses the Association of Firearms and Tool Mark Examiners (AFTE) “Theory of Identification” definition as set forth in the AFTE Journals (July 1992 Volume 24, Number 3 and Fall 2011 Vol. 43, No. 4) to be the generally accepted Criteria for Identification: • 2.2.1 • The theory of identification as it pertains to the comparison of toolmarks enables opinions of common origin to be made when the unique surface contours of two toolmarks are in “sufficient agreement.” • 2.2.2 • This “sufficient agreement” is related to the significant duplication of random toolmarks as evidenced by the correspondence of a pattern or combination of patterns of surface contours. Significance is determined by the comparative examination of two or more sets of surface contour patterns comprised of individual peaks, ridges and furrows. 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. Agreement is significant when the agreement in individual characteristics exceeds the best agreement demonstrated between toolmarks known to have been produced by different tools and is consistent with agreement demonstrated by toolmarks known to have been produced by the same tool. The statement that “sufficient agreement” exists between two toolmarks means that the agreement of individual characteristics 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. • 2.2.3 • Currently the interpretation of individualization/identification is subjective in nature, founded on scientific principles and based on the examiner’s training and experience.
Random/Stochastic Process= Chip Formation= Microscopic Individuality!
Pattern Matching • One reason humans are such a successful species is because we are so good at recognizing PATTERNS. We recognize the faces of loved ones in crowds, we remember faces instead of names. Look at Tetris, child block games, Rubick’s cubes, the list goes on and on. • Firearm and Tool Mark Identification relies on Pattern Matching. • But—this type of pattern matching does not rely on memory! It is performed in REAL TIME on a comparison bridge microscope!
Class Characteristics • Class Characteristics are measureable features of a specimen which indicate a restricted group source. They result from design factors, and are therefore determined prior to manufacture. For Fired Bullets: Rifling twist, width, type (conventional or polygonal), number of grooves. For Fired Cartridge Cases: Shape of firing pin, shape of firing pin aperture, ejector/extractor shape and position, type of machining marks (arched/linear/concentric), etc.
GLOCK Rectangular Firing Pin Aperture Example of a Class Characteristic
Comparison Bridge Microscopic Comparison between Two Cartridge Cases fired in a Glock
Class Characteristics allow the informed expert to easily ELIMINATE firearms as having fired unknown exemplars if the class is different. We don’t hear about this too often in court because when this is the case, the evidence usually is exculpatory in nature and the investigation never makes it that far. • If the class characteristics produced by the tool or firearm are similar, the expert should not eliminate the tool or firearm as a possible source-even if the individual microscopic characteristics are different. This is because surfaces can wear and change over time, and can change extensively via misuse or intentional abuse. Therefore, for instances where known/unknown class characteristics are similar, the outcome may be either inconclusive or an identification. Some out-state labs have a policy where they WILL eliminate based on differences in individual characteristics. This is a point of contention.
Subclass • Subclass characteristics are discernible surface features of an object which are more restrictive than Class Characteristics in that they are produced incidental to manufacture, are significant in that they relate to a smaller group source (subset to the class that they belong), and can arise from a source which changes over time. • Subclass characteristics tend to be gross in nature (not fine or minute). • EXAMPLE: Smith & Wesson MIM firing pins • Examiners learn about and publically share information concerning subclass characteristics among units, departments, and particularly through the AFTE Journal, the AFTE Conference, and the AFTE Forums.
Individual Microscopic Characteristics • Allow for firearm and toolmark identification. Absolutely random in nature (cannot be predicted/from a stochastic process). • Are created through chip formation, random imperfections caused by chips caught within working surfaces, differences in hardness of steel, tool speed (ex. Drilling), accidental imperfections from firing and handling/use, and other mechanical means.
Lone Characteristic Within the FPI of Two Fired Cartridge Cases
Lack of Significant Agreement Between IMC on Two Fired Cartridge Cases
Metal Injected Molding (MIM) Produces a Subclass Mold Relic at the Break Line These relics mimic individual characteristics, and while shared by a unique subset of firing pins (pins made by a specific mold), it is a major cause for concern.
TOOL MARK IDENTIFICATION STRIATED IMPRESSION
VERY Similar Class (Hi-Point most likely). NO Matching Individual Characteristics
One Group of Identified Cartridge Cases had Reamer Chatter Marks that Resembled Fluting
FIREARMS IDENTIFICATION STAMPED IMPRESSION (Firing Pin Impression)
MSP Firearms Unit Facts • All examiners are members of the Association of Firearm and Tool Mark Examiners (AFTE) • All examiners undertake, and must pass--a two year program consisting of study and practical training. The program is modeled after the AFTE training protocols. Two have been trained at the ATF-NFEA (National Firearms Examiner Academy), which is a very prestigious program. • Examiners are proficiency tested twice per year by an outside source. • Examiners work in a laboratory that is accredited to ISO 17025 Standards by ASCLD-LAB, and their units are audited on a yearly basis. • “Measurements that Matter” utilize NIST calibrated equipment, traceable to the BIPM (Bureau International des Poids et Measures). • All examiners abide by two codes of ethics: The AFTE Code of Ethics and the ASCLD Guide to Professional Responsibility. • The former also requires two AFTE members who disagree to attempt a constructive agreement prior to any testimony.
Choosing an Independent Expert • If ethics are important to you (I hope so), is the independent expert a member in good standing with AFTE? • Experience within an actual laboratory setting is important. Have you vetted the independent expert? Do you know anyone in your state who can vouch for him or her? Beware experts from other states who are not members of AFTE and have limited track records. Do your homework!! • Remember that a presented “expert” may lack formalized training , may not be proficiency tested (or may never have been), and may not utilize any type of technical or peer review. Look for an expert who possesses these qualities. • There are many Independent Experts from around the country who fit the qualities you might be looking for. They do work in civil and criminal cases. The following list is a good place to start; they are all Distinguished Members of AFTE: • http://www.afte.org/distmemberreferal.htm#midwest
Contacting an MSP Scientist • Jim Piazza, Barry Wolf, Barney Whitesman, Pat Kirby, Lee Sturtz, and other Mid-Michigan Defense Counsel have personally contacted me prior to trial to discuss their cases. • Only a handful of prosecutors in a 14 county service area frequently contacted me prior to trial. Very few met with me to go over the report findings and discuss significance/etc. • There is nothing in our operations policy which precludes talking with Defense Counsel about casework that has been reported. My employees are friendly, dedicated, and helpful…if you actually ask. • Please don’t be a confrontational jerk if you contact my employees outside of the courtroom context. You don’t need to be.
Crafting Your Plan • ASK the Forensic Scientist! If you are a defense counselor worried about letting your cat out of the bag prior to trial, talk to the expert shortly before the witness hits the stand. We spend a lot of time waiting in the hallway. • CALL or MEET with the Firearm Examiner if you can. Educate yourself about the case. It is FREE. • UNDERSTAND that the Examiner frequently knows much less about the case particulars than you think. Typically, the only cases where the examiner has investigative case knowledge of any depth are those where the examiner worked the crime scene. It can therefore be helpful to speak to the examiner to discover fact-based opinions that could assist your prosecution or your defense.
Asking the Right Questions • Subjectivity-This is an Opinion, correct? • Practical vs. Absolute Certainty-Explain • Inconclusive Findings and the prevalence of firearms that could have fired this bullet etc (Thousands/Hundreds of Thousands/Millions??) • Can you load and fire this bullet in another caliber cartridge (i.e. a 115 grain 9mm Luger bullet in a .357 Magnum case)? • Explore the Possibilities--How could this have happened/are there other things that could account for this occurrence? • Your testing can only place an object at a scene, not a person at a scene, correct? • www.firearmsid.com
