AFTE 2006 Thursday

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www.afte.org > Training Seminar > 2006 Thursday

AFTE 2006 - Thursday June 29

MORNING SESSION

MODERATOR:

JERRY PETILLO, CONNECTICUT DPS CRIME LAB

TIME
TOPIC & PRESENTER AREA/ROOM

6:30 AM
Breakfast

8:00 AM
The Scientific Foundations of Firearms and Tool Mark Identification - Responding to Recent Challenges

Ron Nichols, AFT Forensic Science Laboratory – San Francisco, Walnut Creek, CA

Ron's PowerPoint presentation is available for download here.

MMC Grand Ballroom

Objectives:
There have been several recent challenges to the firearms and tool mark discipline published in the literature that have received varying levels of attention. If one were to examine these challenges, they share common concerns. This presentation will examine those concerns and demonstrate how the discipline has already addressed those concerns or to demonstrate why the concerns are not valid.

Results:
The common concerns that will be addressed begin with the issue of scientific reliability. In answer to this, it will be demonstrated that firearms and tool mark identification is firmly rooted in the application of the scientific method, that repeated testing of the hypotheses related to the discipline have been performed, and such testing has resulted in a standard statement setting guidelines for identification criteria. In support of this several issues will be discussed including coincident correspondence, subclass characteristics, and changing tool surfaces.

Going beyond scientific reliability, critics discuss concerns with what they feel to be lack of adequate validation of the discipline. Under this broad issue they cite concerns with the lack of representative databases and statistical treatment such as that found in DNA. They move on to criticize the lack of well defined error rates and poorly designed proficiency testing. In answer to this, it will be demonstrated that firearms and tool mark identification has been validated. In support of this it will be demonstrated that the issue of representative databases is misplaced, being the product of an inappropriate analogy with DNA.

The issue of statistics will also be discussed, demonstrating that there has been much thought given to this particular topic within the discipline. Many obstacles remain to be solved before statistics can find more widespread use including the type of statistics, issues of randomness and independence as well as acceptable quantitative models for impressed tool marks. The issue of error rates and proficiency testing will be also be discussed with the result being some quite useful information that the courts would find valuable in assisting them in determinations about the reliability and validity of firearms and tool mark identification.

Finally, there will be a discussion of several court decisions dealing with the issue of firearms and tool mark identification. The review of these decisions will demonstrate that the court appears to be capable of properly determining when the needs of the science have been met and where they have not.

Conclusions:
As demonstrated through this response, the material to support the scientific background of the firearms and tool mark identification discipline is available in the relevant professional literature. What remains is for examiners to put this into practice through good, solid practice and then, just as importantly, learn how to communicate the intricacies of the discipline to a non-scientific audience. Even with the wealth of support, the burden is not on the critics to stop criticizing or the courts simply to accept what is said carte blanche. The burden is on the individual examiner to step up to the plate and be effective not only in their casework but also in their ability to communicate this databank of knowledge. It does not speak for itself.

10:00 AM
Break

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Exhibit Hall

10:30 AM
Bullet Holes In Wood: What Can Be Determined From Them?

Lucien C. Haag, Independent Examiner, Carefree, AZ

MMC Grand Ballroom

Objectives:
This presentation will first illustrate the behavior of various types of wood to perforating bullet strikes followed by the various things that can be determined from bullet holes in wood. These include the approximate caliber of the responsible bullet, the direction of fire, bullet composition and some assessment of impact velocity. This presentation is preparatory for the second presentation on the Lincoln Target Board.

10:45 AM
The Lincoln Target Board

Lucien C. Haag, Independent Examiner, Carefree, AZ

MMC Grand Ballroom

Objectives:
In August of 1863 Christopher Spencer had a private meeting with President Abraham Lincoln where he presented his revolutionary 7-shot repeating rifle to the President. The next day Lincoln fired a full magazine at an improvised target fashioned from a pine board. Lincoln was so impressed with the Spencer that he personally endorsing it and set aside General James Ripley’s opposition to the purchase of repeating cartridge guns for the Union Army. The Spencer rifles and carbines became the most dreaded and hated gun by the Confederates who fought the entire war with single shot muzzle-loading rifles and muskets. Spencer retained the target board for many years then sent it to the State of Illinois where it purportedly was lost in the mist of time.

The Lincoln Target Board has been found and the author was allowed to personally examine and photograph it at the Illinois State Military Museum in his home town of Springfield, Illinois. The Lincoln Target Board allows us to see what sort of marksman our 16th president was but the bullet holes in the board raise some question as to just what version of the Spencer rifle President Lincoln fired on that historic and fateful day in August 1863. The knowledge gained from the previous presentation on bullet holes in wood will be used to show what can be reasonably concluded from the dimensions of the bullet holes in this most famous of all targets.

11:00 AM
The Influence of Intermediate Objects Positioned Close to the Muzzle of a Firearm

Matthew Noedel, Noedel Scientific, Puyallup, WA

MMC Grand Ballroom

Objectives:
A study was conducted to evaluate the trajectory of bullets that have been fired through intermediate objects immediately at the muzzle of a firearm. These dynamics were examined in conjunction with an interesting case that involved a homemade suppressor attached to a Browning pistol. A review of the case and the suppressor design will also be presented.

Methodology:
Shooting from a rest through the intermediate target, the trajectory deflection over short distances was measured. These tests were applied to the crime scene of a shooting event.

Results:
Depending on the intermediate and the scene dynamics, these devices may not significantly influence the trajectory.

Conclusions:
The influence of the intermediate in this case was typically not significant over short distances.

11:30 AM
Viewing and Training Tool of Known Match and Known Non-Match Comparison

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

MMC Grand Ballroom

Objectives:
Every firearm and/or tool mark examiner recognizes that known match and known non-match comparison is very important in the course of training. Comparison among the bullets fired from a barrel consecutively and comparison among the bullets fired from consecutively tooled barrels are essential in this type of training. The author made a simple tool to do these types of training. This simple tool does not simulate manipulation of comparison microscope which already exist virtual comparison microscope excellently does, however this tool provides an easy viewer of landmark comparison work.

Methodology:
This tool is made on Microsoft Excel and display the all the six landmarks side by side at a time. Image of 122 bullets from 5000 consecutively fired bullets experiment with Jim Hamby can be compared. These Images consist of base area of landmarks and landmark images compressed in a longitudinal direction are available in this tool. Both colour images from which one can feel three dimensional contour and differential filtered images with which one can easily counting aligned striation are provided. Images of 35 fired bullets from consecutively tooled Ruger ten barrels provided by Brundage/Hamby are also available in this tool. Images from Ruger bullets consists of colour and differential filtered image taken from base area of landmarks 　One only selects number of round of both left side and right side bullets in 5000 bullets comparison tool. Viewer can move alignment of each landmark to line up striation. There are two comparison modes in Ruger bullets comparison. In test mode, one can try blind comparison. In study mode, one can examine difference between KM or KNM bullets pair.

Results:
Quickly browsing of landmark change during successive firing and difference appeared among the bullets fired from continuously tooled barrel will be helpful for training firearm examiner. We can view the comparison results from all the six landmarks at a time with this tool. This capability may be helpful for beginners.

Conclusions:
This type of comparison is already available in sophisticated system such as IBIS. However simple tool on personal computer will be helpful for training use because this type of examination takes a lot of time.

12:00 PM
Lunch (Provided) Exhibit Hall

AFTERNOON SESSION

MODERATOR:

FRANK NICOLOSI, WESTCHESTER COUNTY (NY) DPS

TIME
TOPIC & PRESENTER AREA/ROOM

1:30 PM
Sub-Class Characteristics of Ruger Firearms

Greg Scala, FDLE, Orlando, FL

MMC Grand Ballroom

Objectives:
To inform the discipline of Firearms Examiners about a group of Ruger firearms which posses manufacturing marks that could affect conclusions of identity concerning bullets fired from these firearms. These marks are sub-class in nature however, unlike sub-class characteristics which, by nature represent a limited sample, these marks represent a potentially large number of firearms.

Methodology:
The Author used a combination of methods to learn more about the rifling methods currently used by Ruger and to assess the forensic significance of these methods:
1. Bore casting with silicon rubber from various sample sources with subsequent microscopic comparisons of casts.
2. Phone conversations with factory technical advisors.
3. Personalized tour of Ruger while obtaining pertinent barrel, mandral and silicon casted samples.

Results:
The hammer forging operation at Ruger produces barrels having lands all nearly identical to each other in microscopic detail of the stria parallel to the rifling. This "identity" arises from the mandral which forms the rifling during the forging process. Diamond coated grinders which cut the mandral grooves are the ultimate source of this replicating pattern of stria.

Conclusions:
Although bore casts of Ruger hammer forged barrels display land to land correspondence (within the same barrel) and also display the same amount of barrel to barrel correspondence, the author was unable to demonstrate barrel to barrel identity of fired bullets. The effect of reaming marks in the bore and the crowing operation at the muzzle on these sub-class marks being carried over to fired bullets is largely unknown.

There are a large number of firearms being represented by this rifling method and it is not only used by Ruger. Further study needs to be done on how extensive this process is in the industry and how it affects what we as firearms examiners do.

Examinations and comparisons of fired bullets suspected of coming from a firearm represented by the above group should be done with extreme caution. More importantly, knowledge of the potential risk involved when making such comparisons where sub-class characteristics might be an issue.

2:00 PM
Identification of a Toolmark on Human Skull Utilizing Cattle Blade Bones as Test Medium

Stephen H. Ostrowski, New Hampshire State Police Forensic Lab, Concord, NH

MMC Grand Ballroom

Objectives:
Casework examination trying to determine whether any of the three sharp force implement toolmarks to the head of a homicide victim could be identified as having been caused by a recovered hatchet.

Methodology:
Three sections of skull collected at autopsy were cleaned and examined for evidence of comparable toolmarks. The analysis, comparison, evaluation and verification (ACE-V) methodology was utilized during examination of both the toolmarks and the tool in this case. Mikrosil casts were taken, evaluated and it was determined that one toolmark present on a section of skull was identifiable. Various traditional test cut mediums failed to yield the desired level of straie reproducibility. A local meat wholesaler was contacted and three sheep heads and three cattle blade bones were obtained. Numerous test cuts were made with the evidence hatchet on the animal bone specimens. The test toolmarks were then cleaned, examined, and Mikrosil-casted in the same manner as the evidence bone sections. Further analysis, comparison and evaluation of the casts were conducted using a comparison microscope.

Results:
Test cuts made in the sheep skull specimens were not usable due to the tool completely penetrating the thin bone. Test cuts made in the cattle blade bone specimens produced a desirable level of straie reproducibility. The toolmark on a section of the victim's skull was identified as having been caused by the hatchet in question.

Conclusions:
The findings in this case support the theory that known test cuts in toolmark cases should be made in a material which possesses physical characteristics closely resembling the substrate in which the questioned toolmark was created. Cattle blade bones closely resemble the physical characteristics of human bone. The surface area on these bovine specimens provides ample room to conduct numerous test cuts.

3:00 PM
Break Exhibit Hall

3:30 PM
Firearms-Toolmarks Error Rate Computation

Doug Murphy, Federal Bureau of Investigation, Firearm/Toolmarks Unit, Quantico, VA

MMC Grand Ballroom

Objectives:

A logical method of error rate calculation

A summary of CTS test results since 1991

Implication fo the rates for our profession

Methodology:
By categorizing exam results and a careful analysis of CTS test results, error rates can be calculated. An understanding of these rates and how they're calculated will allow for a more effective admissibility challenge defense.

5:30 PM
Pre-Banquet Reception

7:00 PM
AFTE 2006 Banquet

MMC Grand Ballroom

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