AFTE 2003 Thursday

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www.afte.org > Training Seminar > 2003 Thursday

AFTE 2003 - Thursday May 29

Technical Program

Moderator: Bruce Lampe, Philadelphia Police, Firearms Identification Unit

A SUMMARY FOR VARIATIONS OF BREECH FACE MARKINGS AND FIRING PIN IMPRESSION CAUSED BY THE SAME FIREARM (HEMISPHERICAL FIRING PIN)

Beta (Chi Kung) Tam, Los Angeles Police Department, 3401 San Fernando Rd. Los Angeles, CA 90065

1. Outline of Objectives
To provide an overview on some of the possible variations in breech face marks and firing pin marks produced by the same firearm with hemispherical firing pin so that premature elimination could be avoided.

2. Brief Methodology
The author had started to collect digital images of fired cartridges for about four years. Analysis those images revealed that certain variations repeated consistently. Exemplar images with hemispherical firing pin are gathered and grouped by the movement of the tools making these marks.

3. Summary of Results
The analysis grouped these variations in markings into three types. The first types are marks made by the tool moving vertically. The second type is marks made by the tool moving horizontally. The last types are for variation that does not belong to the above two groups.

4. General Conclusion
Variation in breech face marks and firing pin marks produced by the same firearm have very close relationship to the movement of the firearm during the firing cycle. Close observation of these variations will give us a better understanding of how the marks are made during the firing cycles and therefore avoid premature elimination.

UNUSUAL TOOLMARK COMPARISON

Jan De Kinder and Gerard Migeot - Nationaal Instituut voor Criminalistiek en Criminologie (NICC/INCC), Vilvoordsesteenweg 98-100, B-1120 Brussels (Belgium)

In this presentation, two unusual types of toolmarks comparisons are presented.

Drugs are frequently packed into plastic bags which are sealed using a professional heat sealer. The sealing mark provides a number of characteristics (both class and individual) which are of importance to forensic use. In this presentation a number of results
of positive identifications are shown.

It is known from literature that a paper cutting machine can provide sufficient individual marks to identify the machine which cut a block of paper. In a recent forgery case, the toolmarks present on single sheets of paper were compared to reference sheets cut with a
paper cutting machine. These marks were of the size as the paper fibers composing the paper. A positive identification of the paper cutting machine could be obtained.

MULTIPLE COLLECTOR ICPMS: A NEW TOOL FOR ISOTOPIC ANALYSIS OF BULLET LEAD

Dr. Michael E. Ketterer, Jay R. Vargas, Michael T. Beddow, Darrell W. Smith, Department of Chemistry, Northern Arizona University, Box 5698, Flagstaff, AZ 86011. Lucien C. Haag, Criminalist / Firearms Examiner, Forensic Science Services, Carefree, AZ 85377

The analysis and comparisons of the compositions of bullets and bullet fragments can be useful in forensic work particularly in situations involving a limited universe. Many studies have also examined the provenance of lead using elemental constituents. Antimony is often intentionally added to lead destined for use in bullets as a hardening agent and is thus a class characteristic. Other elements (Sn, As, Bi, Cu and Ag) in trace amounts are individualizing constituents that are generally present as unintended impurities.

Lead exhibits variance in its isotopic composition as the isotopes ²⁰⁶Pb, ²⁰⁷Pb and ²⁰⁸Pb are radiogenic, while ²⁰⁴Pb is not. The latter is used as a reference in the ratios ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb /²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb. While not necessarily unique, the lead isotopic composition is characteristic of a material, and only changes through mixing with lead of a different isotopic composition. Lead isotopic compositions may be especially useful in "limited universe" comparisons where known and unknown specimens are available for comparison. The better the precision of the Pb isotopic data, the more useful the comparison.

A new mass spectrometric technique, multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS), has recently become available as a rapid method for high-precision isotopic analysis. In MC-ICPMS, all isotopes of interest are simultaneously counted using an array of appropriately positioned detectors at the exit focal plane of an electromagnet. This simultaneous measurement optimizes counting statistics and cancels noise introduced by ion beam fluctuations. For Pb, MC-ICPMS can determine Pb isotope ratios with internal precisions of 20-100 ppm (standard error of the mean); this is superior to previous work with single collector ICPMS. MC-ICPMS can be applied to the analysis of bullet lead samples with minimal sample preparation and a throughput of 3-4 samples/hour.

This study presents the use of MC-ICPMS in three ballistics topics: 1) Pb isotopic compositions are surveyed from bullets obtained from manufacturers throughout the world; 2) a case study concerning a fatal hunting accident, where the choice of shooters was limited to two individuals with known ammunition and a few minute lead fragments in the wound track; and 3) the analysis and comparison of the lead in sodium rhodizonate tests derived from ricochet marks on smooth stone with the bullets that caused them.

INITIAL TEST RESULTS FOR 20 NIST RM 8240 STANDARD BULLETS

J. Song, L. Ma, E. Whitenton and T. Vorburger, National Institute of Standards and Technology Gaithersburg, MD 20899

20 RM (Reference Material) 8240 standard bullets are tested by a newly developed NIST bullet signature measurement system. A NIST proposed parameter and algorithm are used for quantifying bullet signature differences between the RM bullets and the virtual bullet signature standard. The virtual standard is a set of six digitized bullet signatures originally profiled from six master bullets shot at ATF and FBI using six different guns. By using the virtual signature standard to control the tool path on a numerically controlled (NC) diamond turning machine at the NIST instrument shop, 20 RM bullets were produced. The NIST proposed algorithm uses auto- and cross-correlation functions (ACF and CCF) for quantifying bullet signature differences. When the compared two signatures are exactly the same (point by point), their CCF optimum value would be equal to 100%. Measurement results showed that for the 120 lands of the 20 RM bullets, the CCF optimum values are higher than 95%, and most of them are higher than 99%. These results demonstrate the high reproducibility of both the manufacturing process and the measurement system for NIST RM standard bullets.

HI-POINT AND STAR AMMUNITION 9; VIRTUAL TOUR CDs

Chris Monturo, Miami Valley Regional Crime Laboratory

The focus of this presentation is to inform the members on how to utilize the Video Compact Disks which they will receive with registration. The disks encompass the manufacturing process of Hi-Point Firearms located in Mansfield, Ohio and bullet manufacturing by Star Ammunition in Indianapolis, Indiana.

TIME TOPIC AND PRESENTER AREA/ROOM RUBBED OUT SERIAL NUMBERS ON 9; FIREARMS

Jan De Kinder - Nationaal Instituut voor Criminalistiek en Criminologie (NICC/INCC), Vilvoordsesteenweg 98-100, B-1120 Brussels (Belgium)

A video demonstration is presented of how a serial number of a firearm was altered. First, the original serial number was grinded away. In a second step, new material was welded into these areas. Finally, the overflow of material was again grinded away and the firearm was subjected to another blueing operation. This procedure prevents a subsequent forensic serial number restoration.

The characteristics of the resulting areas on the firearm are given as
to provide a means to identify these occurrences.

VIRTUAL COMPARISON MICROSCOPE: AN EXERCISE IN FIREARM IDENTIFICATION/ PATTERN RECOGNITION

Scott Doyle, Kentucky State Police & Erik Dahlberg, Dalhberg-IT

In an attempt to provide visitors to my website, www.firearmsID.com, a tool to help them better understand the task of comparing bullets on a comparison microscope I set out to develop an online Virtual Comparison Microscope.

Erik Dahlberg, a Danish software engineer ( http://www.dahlberg-it.com / www.EuroSimulator.com ), and I have developed an online application that allows users to "virtually" compare four "unknown" bullets to test standards fired from four different Ruger P85 semiautomatic pistols. The application allows the user to view side-by-side images of the six different land impressions on the unknown and the standard. These images can be moved around in the "scope" region of the application and direct comparisons of the visible striae can be made.

Users will be asked to find the matching unknown and firearm standard and to find the best match of the six land impressions. Once completed the user will record their matches and submit them to receive a score. Scores will be recorded and the students will have the option of forwarding their score to an instructor if the exercise is used as part of a course curriculum.

Users most likely will include forensic science enthusiasts, students, firearm examiner trainees, and firearm examiners. Because such a broad base of users are anticipated additional information will be asked for that will hopefully allow for the development of a statistical baseline of error rates in novice, trainee, and experts in pattern recognition as it relates to the field of firearm and toolmark identification.

AFTERNOON SESSION

Moderator: James Hamby, Indianapolis-Marion Co. Forensic Services Agency

A NATIONAL VIOLENT DEATH REPORTING SYSTEM LINKING DATA TO SAVE LIVES

Mallory O'Brien, PHD, Associate Director National Violent Injury Statistics System, Harvard School of Public Health, 2501 E. Menlo Boulevard
Shorewood, WI 53211

Mallory O'Brien, PHD, Associate Director National Violent Injury Statistics System, Harvard School of Public Health, 2501 E. Menlo Boulevard Shorewood, WI 53211

Nearly 50,000 violent deaths occur each year in the U.S. We have little, detailed information about them because there is no national uniform reporting system that captures the details of when, where, how, and most importantly, why violent deaths occur. Firearm and toolmark examiners, coroners, police officers, death certificate registrars and others record many pieces of the puzzle, but without a comprehensive usable database, critical information is often left in file cabinets or on computers. The National Violent Injury Statistics System (NVISS) has begun bridging these gaps by coordinating a network of 13 sites across the country that collect and link detailed data from numerous sources in their locality about all violent deaths - homicides, suicides and unintentional firearm deaths. NVISS serves as the model for the National Violent Death Reporting System (NVDRS) just getting underway at the Centers for Disease Control and Prevention (CDC).!
In gathering the facts about the circumstances surrounding each violent incident, NVDRS will take full advantage of the information already being meticulously documented by crime labs, coroners and others. NVDRS will allow us to develop, implement and evaluate various prevention initiatives at the national, state and local level.

THE AFTE WEBSITE, WWW.afte.org

Scott Doyle, Kentucky State Police

This presentation is intended to help AFTE members to better understand how their website works, what information is available to them, and ways they can receive assistance through the website.

All sections, both public and private (member’s area) will be described to members. Instructions on how to register for the member’s area, retrieve lost login information, and edit their online roster information will be given. Also, detailed information on how to use the message boards online will be included.

MARKING SHOULD NOT BE MATCHED

Tsuneo Uchiyama, National Research Institute of Police Science, Kashiwa, Chiba Japan

Origins of marking on expended cartridge cases will be firearms from which fired, machining tools used for making them, various surrounding materials which damaged them before or after firing, etc. Distinguish these origins of markings of expended cartridge cases is essential for firearm identification. Experienced examiner avoids misjudgment using his/her abundant knowledge about mechanism of each firearm and plenty of markings he/she examined before. Even experienced examiner will be perplexed when a new type of gun used in crime which he/she was not encountered with. In this presentation, it is shown that careful microscopic examination is essential to avoid misjudgment using a couple of cases.

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