California Association of Criminalists

GUNSHOT RESIDUE IN THE LAW ENFORCEMENT ENVIRONMENT
Debra K. Kowal, [email protected]

The objectives of this study are to determine 1) the occurrence of gunshot residue (GSR) in the environment of patrol vehicle backseats, 2) secondary transfer from the backseat to an individual and 3) the transfer rate of GSR after an individual is handcuffed and transported in the backseat of a patrol vehicle. As with any forensic evidence collected, it is important to establish the initial integrity of the sample collected. Understanding the law enforcement environment contributions of GSR particles and establishing a numeric value to the transfer rate of GSR will allow us to more accurately interpret GSR evidence. All the analyses were performed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS); a Leica 360 and LEO 435 both equipped with Oxford EDS systems.

The backseat of Los Angeles County Sheriff's patrol vehicles have a molded vinyl "Prisoner Safety Seat" with a small padded area called the cupping area where the hands in handcuffs can rest. Most of the Sheriff's stations that participated in this study had this type of seat. Our sampling of the seat focused on the cupping area and the immediate surrounding area. One sticky lift sample disk was used to collect from both the passenger side and driver side backseat. We visited 11 of the 22 Los Angeles County's Sheriffs sub-stations, where we collected 205 samples from the backseats of patrol vehicles. To date 50 of the 205 samples have been analyzed for GSR. 45 of the 50 backseat samples had consistent GSR particles on them and 4 of the 45 had highly specific GSR particles. Only 5 of the 50 had no GSR particles on them. The mean number of highly specific and consistent GSR particles found on a backseat was 6.6 with a high of 49 and a low of 0.

Secondary transfer of GSR particles from a patrol vehicle backseat to an individual's hands can occur. This was determined by placing a handcuffed individual with GSR on their hands in the backseat of a patrol vehicle for 10 minutes, removing that person and placing another handcuffed individual with no GSR on their hands in that same backseat. The sampling technique used for the backseat was applied to the hands of the individual. We found that 12 highly specific particles and 10 consistent particles of GSR were transferred from the backseat to the second individual's hands. We are currently in the process of collecting hand samples from individual with clean hands that have been handcuffed by an on duty officer that is just ending his/her shift and being placed in the backseat of a patrol vehicle for ~ 10 minutes. We do not have enough samples yet to determine what the transfer rate of GSR is coming out of the above environment, but there appears to be a correlation between officers discharging their weapon and the transfer of highly specific GSR particles. Of the 23 samples collected and analyzed to date, highly specific particles were transferred to the hands of a clean individual when the officer had qualified with their weapon some time during their shift.

From these preliminary findings it is clear that GSR is in the environment of patrol vehicle backseats. Secondary transfer of GSR particles from a patrol vehicle backseat to an individual with clean hands can occur. The transfer rate of GSR particle is yet to be determined, however with these preliminary results available the interpretation of a positive GSR sample from an individual coming out of the law enforcement environment may be clarified by asking a few question of the arresting officer about his shift that day.

A COMPARATIVE STUDY FOR THE RECOVERY OF TRANSFERRED PUBIC HAIRS AFTER SEXUAL INTERCOURSE USING DIFFERENT COMBING DEVICES
Cherie Will, Los Angeles Police Department

Pubic hair that has transferred from a rapist to the victim is an important piece of associative evidence linking these two people. Prosecutors and investigators rely on forensic hair examiners to explain the likelihood that pubic hair from the perpetrator will transfer to the victim and vice versa. The collection rate for transferred pubic hairs using either of these combing devices has not been obtained in controlled studies or sexual assault casework. This study compared to the rate of pubic hair transfer collection utilizing two different combing devices. Sampling was conducted by a limited number of consenting heterosexual couples immediately following intercourse on 10 occasions. The two combing devices consist of a plastic comb with short closely spaced teeth and a nylon brush with numerous rows of soft bristles. Comparative microscopy was conducted on the 874 pubic hairs collected in 180 samples. Samples with transfer hairs collected with the brush (16/90 or 17.8%) outnumbered the samples with transfer hairs collected with the comb (8/90 or 8.9%) by a ratio of 2:1. Transfer hairs in female samples (16.7%) outnumbered the transfer hairs in the male samples (10.0%). Only once were transfers observed simultaneously between both male and female.

Based on the results of this study, the brush was shown to be a more effective tool for the collection of transferred pubic hair.

THE CASE OF THE �MATCHING" MATCHES
Marianne Stam, CA Department of Justice, Riverside

In December of 1999, four arson fires were set at Joshua Tree National Park that resulted in severe damage to three government buildings. Wooden matches were left at the scenes and a suspect was subsequently arrested and found to have boxes containing similar looking matches in his pocket and vehicle. The National Park Service requested that our laboratory compare the matches left at the scenes with those from the suspect and his vehicle.

Match head color, match length, stick width, shape and color and the elemental and organic composition of the match heads were examined using stereomicroscopy, polarized light microscopy, FTIR microscopy and SEM/EDX. The samples examined included matches from the two boxes of Coleman brand matches found on the suspect and in his vehicle, four partially burned or unburned matches found at the scenes, six packages of different waterproof "exemplar" matches representing four different manufacturers, and six boxes of non-waterproof "exemplar" stick matches from different countries/ manufacturers.

The matches found at the scenes were similar visually and chemically to those found in the suspect's pocket and vehicle. They differed in match head color and some in match head polymer type from the twelve different samples of waterproof and non-waterproof exemplar matches, thereby providing some indication as to their "uniqueness". (The "exemplar" matches were not analyzed for their elemental compositions).

During the analysis of the matches in this case, it was found that Match head color differs considerably among different waterproof match brands and is therefore a very good discriminating tool. Also, although published literature discusses using elemental analysis as a means for match comparisons, match head polymer coatings were found to be a discriminating tool - especially between waterproof and non-waterproof matches. In addition, at least in Southern California, there appears to be a limited number of waterproof match brands available.

HUMAN DNA ANALYSIS OF DUST SAMPLES BY HLA DQA1+PM
George Hou, Los Angeles County Sheriff's Department, Scientific Services Bureau

Human DNA analysis continues to be a powerful tool in human identity testing, and has been applied to various types of biological forensic evidence. Dust is a potential source for human DNA. It is ubiquitous in the environment and is largely composed of organic matter. In this project, dust samples were collected from various locations and DNA was isolated by the combination of aqueous Proteinase K digestion followed by an organic extraction method. Quantitation was performed using the PE QuantiBlot™ slot blot kit. PE AmpliType® DQA1 +PM kit was used in the amplification and typing of the samples. Large amounts of dust were collected at certain areas. Human DNA was then quantified and amplified for genetic typing. Results indicate that the yield of human DNA varies, depending on the particular location sampled. Quantitative studies of samples show that there appears to be a positive correlation between the amount of dust analyzed and the amount of human DNA detected. The final objective of this study involved human DNA analysis of DQA1+PM types obtained from single source human blood deposited on dusty surfaces in various locations.

ONE STEP ABA CARD p30 TEST
Jon Babicka, Los Angeles Police Department Crime Lab

The LAPD Serology Unit conducted a validation study on the One Step ABA Card p30 Test. The LAPD Serology Unit determined that the One Step ABA Card p30 Test is an acceptable alternative to the p30 Crossover Electrophoresis procedure. The validation study revealed: 1) the One Step ABA Card p30 Test is more sensitive than p30 Crossover Electrophoresis, 2) both the One Step ABA Card p30 Test and the p30 Crossover Electrophoresis are specific for primate PSA and human PSA, 3) Urine, blood, saliva will not prevent the One Step ABA Card p30 Test from giving a positive result if semen is present in the mixture.

AN EVALUATION OF VARIOUS GRIESS AND MODIFIED GRIESS TEST PROTOCOLS
James Carroll, Los Angeles County Sheriff's Department, Los Angeles, California

This article examines various protocols and test media used for the Griess test as well as the Modified Griess test and compares the results obtained from each. The Modified Griess protocol and test media as written by John Dillon and taught by the FBI was compared to the alternate protocols in the FBI GSR Manual as well as those used by other agencies in terms of ease of use, quality of results, and cost. Also, the ease of use and quality of results obtained with the Griess test was compared to that of the Modified Griess test. The observations made by the author are that the Griess test has distinct advantages over the Modified Griess test in terms of visibility and increased contrast of point reactions against the background. Certain protocols and test material also had distinct advantages over others. Those found to be superior include the use of desensitized photographic paper as taught by the FBI as well as a technique developed and used by Robert Shem of the Alaska Department of Public Safety.

THE IMPORTANCE OF PHYSICAL EVIDENCE IN A 1996 CHILD MOLESTATION CASE
E. Swanson, Los Angeles PD, Scientific Inv. Div.

The initial crime laboratory analysis on this case began on December 30, 1996 with a routine sperm and semen search of several articles of clothing belonging to a three-year old. Spermatozoa, in quantities sufficient to perform DNA analysis, were detected on one item, an undershirt. DNA results included the victim's biological father. The history of this case is followed from reporting through medical treatment; DNA analysis and adjudication.

SWGDRUG UPDATE: FALL 2000
Jerry Massetti, CA State Dept. of Justice, California Criminalistics Institute; Gary Chasteen, Los Angeles County Sheriff's Department Crime Laboratory

Developments from the October 2-5, 2000 SWGDRUG Conference will be reported on and discussed. SWGDRUG core group members met in Vienna, Austria to evaluate the process to date. It revisited current recommendations and comments, which were received from the forensic science community. This was the third annual meeting of the core group. So far, three subcommittees have prepared recommendations: Quality Assurance; Training and Education; and Methods and Reports. These recommendations and other information about SWGDRUG are posted at www.SWGDRUG.org.

DETECTION OF IGNITABLE LIQUIDS FROM SMOKE RESIDUE BY LARGE VOLUME STATIC HEADSPACE
Dan Cardin, 2207 Agate Ct. Simi Valley, CA 93065

Carbon is liberated and deposited on surfaces during a fire. The objective of this study is to determine if those carbon deposits adsorb residue of ignitable liquids and if those same compounds are in sufficient concentration to be analyzed by Large Volume Static Headspace and GC/MS. This would minimize the need for determine the exact point of origin for the collection of fire debris for ignitable liquid detection and could extend the time in which ignitable liquids could be recovered from a crime scene. Samples of window glass from two rooms containing smoke residue were collected 24 hr. after fires were extinguished and stored in 380c.c. glass sample jars. One of the rooms was ignited without a flammable liquid; the other was ignited with a gasoline-diesel mixture. 100 cc of heads pace was removed from the sample jars and concentrated by a series of cryogenic traps and analyzed by GC/MS. The data show recoverable amounts of ASTM class 2 and class 5 compounds in the room in which the ignitable mixture was used. This method of detection would be useful in cases where the ignition source has been disturbed in an effort to extinguish the fire and could extend the time in which ignitable liquids could be recovered from a scene.

CHROMATOGRAM MATCHING AS A GC/MS TOOL FOR AUTOMATED IDENTIFICATION OF ACCELERANTS IN ARSON STUDIES
Duane Mauzey, ThermoQuest Corporation

This paper presents a system which facilitates the work of forensic analysts in arson investigations. Standards and unknowns samples are acquired by GC/MS and processed by using pattern-matching software in order to reduce the analyst's workload. Data processing and data review conform to current guidelines and working practices in arson analysis.

COMPARISON OF 4000 CONSECUTIVELY FIRED, STEEL-JACKETED BULLETS FROM A 9X18mm MAKAROV PISTOL
Brett Doelling, Department of Criminal Justice, California State University, Los Angeles

4000 Russian manufactured, steel-jacketed 9x18mm Makarov rounds were fired through a Hungarian manufactured PA-63 semiautomatic pistol manufactured to accept the Makarov load. Every hundredth round fired to the 4000th was collected and compared back to the first.

After 4000 rounds it was still possible to identify a projectile back to the baseline as per Biasotti and Murdock�s recommendation of a minimum of one 6 line run or two 3 line runs for identification. Maximum run length was observed to decline with the logarithm of consecutive rounds fired.

Shallowly etched individual characteristics tended to persist longer than deeply etched individual characteristics. New individual characteristics were found to develop and face as the barrel wore.

Skidmarks on the bullets tended to yield fewer, longer runs while land impressions on the bullets tended to yield a greater number of shorter runs.