AFTE 2002 Wednesday

AFTE 2002

Meeting Daily Summaries

WEDNESDAY May 29, 2002

Day four of the AFTE Training Seminar and another full day of papers. See the abstracts below. The evening's activities included a private tour of the Alamo for AFTE members and family.

Technical Program After-hour activities

TECHNICAL PROGRAM, Morning Session

Moderator: Mark Bohaty, Nebraska State Patrol Crime Lab, Lincoln, NE

VALIDATION OF THE EXAMINATION OF VICTIM’S GARMENTS IN SHOOTING INCIDENTS

Reggie Beijer, Scientific Investigator, GSR, NFI Netherlands

The investigation of victim’s garments in shooting incidents is (within the NFI) mainly a visual and therefore subjective process when we are dealing with an entrance-hole or an exit-hole determination. The rules of our quality system, Sterlab, prescribe a validation for all the methods applied. Since there were no specific rules for the validation of this kind of investigation, the process outlined below was followed:

We shot from several distances through five different kinds of garment, creating a total of 120 shooting holes. The majority (90) of these shooting holes were prepared for examination.

Three “identical” test garment sets were assembled. Every set contained all five garments, and entrance-holes as well as exit-holes. Each set was given to a different investigator for examination following the normal procedures.

In one case, investigator A interpreted an entrance-hole as an exit-hole and an exit-hole as an entrance-hole. In another case investigator B concluded he was dealing with a gunshot hole, but could not distinguish between the entrance-hole and exit-hole. These failures occurred in particular with knitted garment. The other 86 examinations resulted in correct conclusions.

Bullet holes in knitted garments are difficult to assess, and should therefore be given extra attention. In daily casework wrong interpretations will normally not appear, because a second investigator will check each garment. We are convinced that the investigation method described above is well validated.

CONSECUTIVELY MADE KNIFE BLADES, PART 1

Evan Thompson and Richard Wyant, Washington State Patrol Crime Lab, Marysville, WA

This presentation is the first of two, which builds on the study of the ten consecutively made Ruger barrels that David Brundage formulated a number of years ago.

One hundred forty serrated knives were obtained, test cuts made on rubber sheeting, and the individual characteristics from each of these cuts microscopically compared.

Secondly, ten consecutively made serrated Benchmade knives were observed being made first hand, collected, and test cuts made by each of these ten knives. Two hundred sets were made up that will be distributed at the 2002 AFTE Training Seminar.

A CRITICAL REVIEW OF COMPARATIVE BULLET LEAD ANALYSIS

Dr. Rick Randich, Forensic Material International, Manteca, CA

Comparison of the minor and trace element compositions of bullet lead alloys has been used by some forensic examiners to make definitive positive associations between bullets or lead fragments at a crime scene and samples of bullets linked to a suspect. Such conclusions have been based on the elemental analysis of small, isolated groups of bullets with no consideration of the metallurgical processes involved in the production and refining of the bullet lead alloys. No foundation has ever been established to show that “sources” of bullet lead alloys are unique or individualized enough to positively identify a single common “source” for various groups of bullets. An understanding of the metallurgy of lead refining shows that the elements quantified in the forensic analysis are carefully controlled in the refining process and that there is no reason to expect unique “sources” of bullet lead alloys. It also shows that there are logical reasons why some elements have been found to be more “discriminatory” than others. Data for lead alloys supplied to two major ammunition manufacturers confirm that multiple indistinguishable shipments of lead alloys from secondary lead refiners to the ammunition manufacturers are made each year and over a period of many years. The data also demonstrates that distinguishable compositions can come from the same melt or “source” of lead alloy. These results clearly indicate that bullets with indistinguishable compositions could have come from different lead “sources” produced in the same or different years. Furthermore, the observation that two bullets have a distinguishable composition does not necessarily mean that they came from a different source.

The results show that the forensic examiner using a method of bullet lead alloy elemental analysis which quantifies up to six elements is restricted to concluding only that indistinguishable bullets might have come from the same “source”, not that they did come from the same source. In addition, it is quite reasonably possible that multiple bullets with similar but distinguishable compositions could have come from the same “source.” It is clear that there is no scientific validity to any conclusions more positive that attributing the possible association as to a common source among bullets from different samples. An understanding of the metallurgical principles operative in the melting/casting process, as well as the data acquired for this study, indicate that any forensic conclusions which associate unknown bullets with the “same source”, and/or “same box” should fail most or all Daubert criteria

BALLISTIC FINGERPRINTING DATABASES

Dr. Jan De Kinder, Nationaal Instituut voor Criminologie, Brussels, Belgium

A number of questions regarding the setting up of ballistic fingerprinting databases are discussed. These questions can be classified into three categories: (1) concerning the efficiency of such databases, (2) forensic issues and (3) procedural issues to be dealt with. The current New York State legislation is used as an illustration of the choices to be made when setting up a ballistic fingerprinting database. European data from the possession and use of firearms at crime scenes will be used to support the three arguments formulated against the installation of a ballistic fingerprinting database.

34th ANNUAL AFTE SEMINAR

Adrienne Williams and Carl Rone, Philadelphia Police Crime Lab, Philadelphia, PA

The 34th Annual training seminar will be held in Philadelphia Pa. at the Adams Mark Hotel, May 25-30, 2003.

SAFEGOM: A GENUINE WEAPON OF TERRIBLY EFFECTIVE DEFENSE

Adrienne Williams and Carl Rone, Philadelphia Police Crime Lab, Philadelphia, PA

This presentation presents information on a unique firearm that was submitted to the unit for identification and examination.

Technical Program, Afternoon Session

Moderator, Joe Saloom, Alabama Dept. of Forensic Services, Montgomery, AL

FIRING PIN ROTATION AS A MEANS FOR DETERMINING FIRING SEQUENCE

Deborah Chaklos and Dr. Robert Levine, Allegheny Co. Coroner’s Office, Pittsburgh, PA

Firing sequence may be determined for cartridge cases based on a predictable pattern of firing pin rotation. This may extend to bullets, as well, based on the assumption that a bullet may be identified to the cartridge case from which it was fired. Firearms with rotating firing pins were selected and the following steps were taken to conduct the research:

firing pin springs were examined,

cartridges were numbered and test fired in order,

cartridge cases were examined and the firing pin rotation pattern was mapped,

Mikrosil casts were made of the inside of the cartridge cases, and

bullets were compared with the casts of the cartridge cases.

Each of the firearms used in the study displayed a one-directional pattern of rotation. Some rotated clockwise and others rotated counterclockwise. Also, rotation seemed to be independent of spring type/orientation.

SEM EDS ANALYSIS OF GSR FROM HEAVY METAL FREE PRIMERS

Ron Fazio, Ft. Worth Police Dept. Crime Lab Ft. Worth, TX and David Garrett, University of Department of Material Science

There are an increasing number of lead and heavy metal free ammunition components available in today's market. Since SEM EDS analysis is often used to search for GSR, it is important to know what, if any, information can be gained from residues of heavy metal free primers. In this study we used SEM EDS analysis of one particular brand of heavy metal free primer to show its composition, and to determine if any GSR particles unique to the primer could be located after discharge. Following previous isolation methods developed by Luke Haag, we used SEM EDS analysis to examine bullet wipe from both lead and 'lead-free' bullets fired from a heavy metal free primed cartridges. SEM EDS results indicate typical GSR can still be found and that no GSR particles unique to the heavy metal free primer could be reliably located.

CLARITY THROUGH COLOR CODING

Louise Walzer, Jefferson Parish Sheriff’s Office Crime Lab, Metairie, LA

Communicating our findings to investigators, and to jury members is an essential part of our profession. Many of us have experienced the headache of receiving a police SWAT shooting that consists of multiple same caliber weapons and an overwhelming amount of bullets and fired cartridge cases. Color-coding the evidence can greatly reduce potential mix-ups, organize our results, as well as communicating our findings. This method of color-coding bullets, fired cartridge cases, and weapons can also be used to reconstruct the shooting scene through the use of PowerPoint. This presentation will focus on the importance of using both the color-coding method and PowerPoint in organizing evidence, simplifying confusing cases, and conveying a clear concise presentation to the jury.

DIESELING OF AIRGUNS USING COMMONLY AVAILABLE FUELS

Robert Caunt, Vancouver Police Dept. Forensic Unit, Vancouver, BC, Canada

Introducing a variety of flammable liquids into the cylinder of a spring piston air rifle and measuring the velocities of the projectiles confirmed the phenomenon of dieseling. It was found that certain fuels will spontaneously diesel, yielding a boost in velocity of as much as twice the standard velocity. The occurrence of dieseling is dependent on a number of factors, but most importantly the properties of the fuel. Some fuels spontaneously combust, while others need a secondary source of ignition.

TEXAS HISTORICAL REVIEW IN COSTUME

Tom Jackson, Texas Living Historian, San Antonio, TX

Take a look at Texas history and events leading up to and following the siege of the Alamo with a living historian. This presentation is a must as great lead-in to the Alamo Tour.

After-Hour Activities

ALAMO TOUR

The host committee arraigned a private tour of the Alamo for members and guests.