86th SEMI-ANNUAL SEMINAR (Fall 1995)
CALIFORNIA ASSOCIATION OF CRIMINALISTS
Program Coordinators: Greg Matheson and Raymond Davis; Program Presenters and Participants: Richard Konieczka, Raymond Davis, Steven Lee, Ph.D., Robin Cotton, Ph.D., and George (Woody) Clarke
Conversational DNA is a three hour consolidation of workshops, technical presentations and audience participation all working together to improve the understanding of DNA and its presentation before the courts and the public. DNA is a highly complex and difficult subject to understand. Even when understood, it is not easy to explain simply and clearly. Richard Konieczka is a communications expert who will provide his insight on how to present a difficult topic in a clear and comprehensible manner. Raymond Davis is a Supervising Criminalist with San Mateo County Criminalistics Laboratory and an associate of Mr. Konieczka in teaching courtroom testimony skills. He will be providing information on how to relate to your audience. Dr. Robin Cotton of Cellmark Diagnostics and Dr. Steven Lee of the DOJ BFS Berkeley DNA Laboratory will be working as a team to lay a foundation for the understanding of DNA technologies. San Diego Deputy District Attorney George (Woody) Clarke will be providing the history of DNA's interesting trip through the legal system. Finally, a panel discussion, consisting of various members of the legal system, from detective to attorney, will describe their perception of what they want and need from DNA as an investigating and prosecuting tool. The format will be free form, with the various presenters interacting with each other throughout the allotted time.
EVALUATION AND ORGANIZATION OF THE EVIDENCE ASSOCIATED WITH THE SIMPSON CASE
Lisa Kahn, Deputy District Attorney, Los Angeles County
HANDLING HIGH PROFILE CASES: A TEAM APPROACH
Lakshmanan Sathyavagiswaran MD, and Steven Dowell, Los Angeles County Department of Coroner
As Chief Medical Examiner- Coroner of Los Angeles County, Dr. Lakshmanan has been involved with many complex cases, several of which were high profile. He will share his experiences and insights of handling those cases. Preparation for courtroom presentation as applicable will be discussed.
The interaction between criminalists, toxicologists, and investigators will be discussed. Additionally, a protocol for high profile cases that has been developed will be presented.
FORENSIC CASEWORK ANALYSIS USING STR'S, DQα, AND PM IN COMBINATION
Robin Cotton, Ph.D., Anjali A. Ranadive, Melisa A. Weber, & Charlotte J. Word, Ph.D. Cellmark Diagnostics
Analysis of Polymorphic genetic loci using the polymerase chain reaction (PCR) enables results to be obtained from small and/or degraded samples. PCR analysis of multiple polymorphic loci has significantly enhanced the amount of information obtainable from biological evidence. The Amplitype® HLA DQα Forensic DNA Amplification and Typing Kit and the Amplitype® PM PCR Amplification and Typing Kit allow typing of six polymarker loci using a reverse dot format. The recent availability of reagents to amplify short tandem repeat (STR) loci such as the HUMCSF1PO, HUMTPOX, and HUMTH01 triplex (CTT) using Geneprint™ STR systems adds additional loci which can be analyzed using the PCR. Although validation studies have been conducted using the CTT triplex, limited data was available on the efficiency of amplification of the CTT triplex in comparison to the DQα and PM systems using casework samples. Therefore, the STR analysis at Cellmark Diagnostics was initially implemented only on evidence samples where a sufficient amount of DNA was extracted to complete both DQα and PM analysis which was then followed by STR analysis.
To date we have analyzed twelve cases (approximately 44 samples) using this approach. Approximately one half of these samples were evidence samples and one half are known samples. One half of the evidence samples are sexual assault samples. DNA extractions were done using phenol/chloroform or Chelex following Cellmark's standard operating procedures. DNA quantification using the Quantiblot™ kit was performed on all samples.
Samples containing as little as approximately 0.1 ng of DNA, as measured by the slot blot, produced results in all three systems. All samples which produced results using DQα and PM also produced results using the CTT triplex. Additionally, as would be predicted from validation studies, equivalent sensitivity for detection was found in both the PM and STR systems. Use of the two detection methodologies together helped confirm the presence of minor mixture components
Thus far, all inclusions using DQa and PM have also been inclusions using the CTT triplex. Based on a database of 105 Caucasians and 98 African Americans, the most common frequencies expected for these combined systems is 1 in 46,000 for Caucasians and 1 in 156,000 for African Americans. The STR CTT triplex is as robust as the DQα/PM systems. The use of two types of detection systems provides additional information for the interpretation of mixed samples.
ANALYSIS OF MEXICAN, GUATEMALAN, AND EL SALVADORAN POPULATIONS FOR NONRANDOM ASSOCIATION OF ALLELES
Donald T. Jones, San Bernardino Sheriff's Scientific Investigation Division
A total of 260 Hispanic samples (100 Mexican, 72 Guatemalan, and 88 EI Salvadoran) were typed for seven genetic markers: esterase D, phosphoglucomutase I, erythrocyte acid phosphatase, adenosine deaminase, adenylate kinase, group specific component, and DQa. The results were examined for nonrandom association of alleles using the observed variance in the number of heterozygous loci for each subgroup as well as the entire data set. No association was detected among the seven markers in any subgroup or in the total:
S2K MEXICAN = 1.252, 95% limits 0.869 -1.507
S2K EL SALVADORAN = 0.955, 95% limits 0.834 - 1.432
S2K GUATEMALAN = 1.296, 95% limits 0.881 - 1.507
S2K HISPANICS = 1.165, 95% limits 0.988 - 1.377
PREVENTION OF SELECTIVE PROBE SIGNAL REDUCTION ON AMPLITYPE® PM AND HLA DQa1 TYPING STRIPS
Rebecca Reynolds, Ph.D., Michael Grow, and Vince Phillips; Roche Molecular Systems; 1145 Atlantic Avenue, Alameda, CA 94501
Alleles of the HLA DQa1, LDLR, GYPA, HBGG, D7S8, and GC loci can be detected using sequence specific oligonucleotide probes immobilized on a nylon membrane strip. In many cases, interpretation of typing results is dependent not only on the presence of probe signals, but also on their relative intensities. Because probe signal intensity is an essential consideration for interpretation, factors that can influence it need to be identified. Clearly, the time and temperature of the assay steps and the salt concentration in the typing solution can affect probe signal intensity. Also, if heat-denatured PCR products are allowed to cool for several minutes, the strands will reanneal and become unavailable for binding to the probes immobilized on the strips. However, the selective loss of GC B and HLA DQA1 4.1 probe signals observed after shorter cooling times cannot be explained by these factors. We demonstrate that following heat denatureation of PM PCR products there is sufficient residual Taq DNA polymerase activity to extend primers as the solution cools and that this primer extension occurs at a more rapid rate than PCR product reannealing. Primer extension across probe binding sites will prevent hybridization of the PCR product to complementary probes on the strip. We recommend a simple modification to the Amplitype® typing protocol to ensure all probe binding sites will be available for hybridization.
SHORT TANDEM REPEAT (STR) POLYMORPHISM ANALYSIS USING ENERGY TRANSFER FLUORESCENT PRIMERS
J. Atherton Wallin (1), Y.Wang (2), R. Mathies (2), and G.F. Sensabaugh, Ph.D. (1); University of California, Berkeley
We have demonstrated previously the advantage of Energy Transfer (ET) primers in STR analysis using both slab gel electrophoresis and capillary array electrophoresis. ET primers excite at a single laser wavelength yet have distinctly non-overlapping and intense emissions, making unambiguous multi-color detection possible. This feature can be exploited in detecting sample and standard and/or multiple samples in the same lane or capillary. Fluorescence detection also allows electrophoretic patterns to be represented as electropherograms; comparison of peak intensities aids in the interpretation of mixed samples.
In this presentation, we extend our studies using the TH01 marker as a model system and additionally demonstrate multicolor detection of multiple STR loci, including CSF, D18S51, FES, TPO, VWF, and D20S85. We have used a CAE unit with a confocal fluorescence detection system; fluorescence detection on slab gels has been achieved using the FluorImager 575 (Molecular Dynamics). The dyes used in primer labeling cause electrophoretic mobility shifts in PCR products; mobility shifts are observed between ET labeled PCR products and non-ET fluorescein dye-labeled TH01 ladder (Promega). Mixtures of heterozygote samples (both with and without common alleles) were analyzed quantitatively to determine parameters for the characterization of mixed samples.
1=Forensic Science Group, School of Public Health; 2=Chemistry Department
DIRECTIONALITY DETERMINATION OF A BULLET STRIKE ON SOFT BODY ARMOR AND IDENTIFYING A BULLET FROM A BARREL THAT WAS DAMAGED AFTER FIRING
Scot Armstrong, California Department of Justice
In the spring of 1994 an officer with a small central coast police department reported that he had been shot by an unknown assailant. The bullet that struck his vest was submitted to the laboratory so that a list of weapons that may have fired it could be compiled. The list included three weapons, one of which was his backup pistol. His pistol was submitted with a part missing, the barrel hammered out of round, and deep scratches in the muzzle end of the barrel. The pistol was restored to operating condition. Test fired ammunition could not be identified to the pistol. However, by pushing a lead bullet into the undamaged breech end of the barrel and pushing it back out, an identification was made. The officer's soft body armor showed evidence of directionality and indicated that the bullet would have had to pass through the unbroken windshield of the patrol unit. The damage to the vest was consistent with it being shot when it was hanging up with no backing material. The hole in the shirt did not line up with the hole in the vest. Finally, the wound received by the officer was not consistent with a bullet striking a vest. The officer pled guilty and received a felony conviction.
OBSERVATION OF .22 CALIBER GUNSHOT RESIDUE ON FABRIC TARGETS BY SCANNING ELECTRON MICROSCOPY
Bryan Burnett, Forensic Science Consulting Group
Preparation of fabric for viewing in the scanning electron microscope can now be accomplished in minutes(1) without the need for carbon or metal coating. Fabric associated particles, smaller than 0.2 microns, can be observed and analyzed for elemental composition using this technique.
Burnett(2) showed that for close-range pistol shots to fabric using jacketed 9 mm and .357 ammunition, much of the gunshot residue (GSR) impacting the target is molten. However, a study with .22 LR ammunition fired by pistol shows a different pattern. Almost all the .22 ammunitions observed produce an abundance of submicron GSR which is not molten when these particles impact the target. For some .22 ammunitions, the GSR particle size and form is remarkably uniform whereas with others there is a diversity of particle sizes and forms. Distance between the muzzle and target is also a factor on the nature of the particles deposited on the target. Most .22-generated GSR likely becomes airborne during normal shooting activities and, due to the submicron size, is respirable to the lower airways. Such ammunition can pose a serious health hazard if the shooter or bystanders are downwind or stay within a GSR cloud.
1=Burnett, B.A., Proceedings of the American Academy of Forensic Sciences, 1995, 1:85.;
2=Burnett, B.A., Journal of Forensic Sciences, 34(4):808-822
JIN BU HUAN POISONING: A TOXICOLOGICAL ANALYSIS OF TETRAHYDROPALMATINE
Daniel T. Anderson, MS; Los Angeles County-Dept. of Coroner
Tetrahydropalmatine (THP) or Jin Bu Huan Anodyne is an alkaloid found in plants of the Carydalis species. The drug is considered to be a natural herb; part of traditional Chinese medicine with sedative and tranquilizing effects. It has been around for more than 1000 years as an analgesic, but only available in the United States for the past ten years.
Documentation of the drug's involvement in patients is limited only to toxicity, not lethality. This paper will present a case study report involving a female who committed suicide with a lethal ingestion of Tetrahydropalmatine.
The analysis of Tetrahydropalmatine consisted of a n-Butylchloride extraction procedure; screening and quantitation on a GC/NPD. Confirmation of the drug was performed on a GC/MS by comparison to a purified Jin Bu Huan Anodyne tablet.
The Tetrahydropalmatine concentrations detected in postmortem blood of a 50 year old female were 7.2 mg/L. The gastric levels suggested that there was 3.8 g or 141 pills ingested. To my knowledge, this is the first reported fatality involving the drug, Tetrahydropalmatine.
MITOCHONDRIAL DNA TYPING USING SEQUENCE-SPECIFIC OLIGONUCLEOTIDE PROBES
J. Varlaro, BS, E. Clark, Ph.D., T. Marschak, BA, S. Rubin, MA, & R. Reynolds, Ph.D.; Roche Molecular Systems, Human Identity Group
Mitochondrial (mt) DNA analysis is extremely valuable to the characterization of biological samples containing a small amount of DNA or highly degraded nuclear DNA. Since mt DNA occurs in high copy number (1,000 -10,000 copies per cell), it is possible that a mt DNA type can be obtained when a nuclear DNA type cannot. Mitochondrial DNA is also useful in the identification of human remains (e.g., missing persons, mass disaster) not only because of its high copy number but also because it is inherited matrilineally; all maternal relatives will share the same mt DNA sequence as the individual in question and can serve as a reference. We are developing an immobilized sequence-specific oligonucleotide probe-based assay to detect sequence polymorphisms in the hypervariable region II (HVII) segment of the mt DNA control region. A panel of fourteen HVII probes, immobilized as lines rather than dots, yields a power of discrimination comparable to DQa (approximately 0.94). Consequently, this HVII test can serve not only as a screen prior to mt DNA sequencing but also as a valuable PCR-based DNA typing test for the routine analysis of bloodstains and hairs. An instrument recently developed for automated strip hybridization, wash, and color development, has greatly reduced the amount of "hands on" time of assay. Future developments will provide for computer scanning and typing of the HVII strip to further simplify (automate) the assay and maximize throughput. Results will be presented that demonstrate the assay's high sensitivity and its ability to amplify samples containing Taq DNA polymerase inhibitors, as well as typing results generated from the automated typing procedure.
THE EFFECT OF CHLORINE-CONTAMINATED STRIPPING SOLUTION ON SUBSEQUENT DNA HYBRIDIZATION
Aceves, M., Hosseinzadeh, A., Butler, J., Piucci, M., and Steinberger, E.M.; California Department of Justice, Bureau of Forensic Services
The RFLP analysis of offender database samples and casework requires the hybridization of genomic DNA with 32P- labeled DNA probes. To allow sequential probing with up to twelve probes, membranes are "stripped" with a 95°C solution of 0.5% SDS and 0.1 % SSC after each hybridization and autoradiography. This process removes the radioactive probe from the membrane without affecting the membrane-bound genomic DNA.
Recently, an incident had occurred when membranes which had undergone the stripping process produced no signal or only a very weak signal on the autoradiogram upon subsequent hybridization. A problem with the stripping solution was suspected, since membranes hybridized for the first time (virgins) produced the usual strong signal.
The first series of experiments designed to test the components of the stripping solution yielded negative results. Based on reports from the quality control personnel, there was a possibility that the high purity water supply could have been contaminated with chlorine from the sanitization process of the MiIIi-Q UF Plus unit. It was determined that, when water containing as little as 2 PPM chlorine was used for the stripping solution, the membranes lost the ability to produce a signal in autoradiography.
A weekly sanitation of the UF cartridges using a chlorine tablet is a required maintenance procedure. To ensure the complete absence of chlorine in the final water product, we instituted a weekly orthotolidine color test, adequate to detect chlorine at concentrations from 12 PPM to 0.2 PPM. Absence of chlorine is determined by a coloration equivalent to <1.0 PPM.
CLIC - CLANDESTINE LABORATORY INVESTIGATING CHEMISTS
Jerry Massetti, California Department of Justice, Fresno Regional Laboratory
The association known as the Clandestine Laboratory Investigating Chemists is a vibrant organization of more than 350 forensic scientists pooling knowledge essential to the investigation of clandestine drug laboratories. Since its incorporation five years ago, members have joined from 30 states and a dozen countries.
In addition to its quarterly journal, a series of monographs have been compiled on a variety of topics including a guide to clandestine lab investigation, phenethylamines, phencyclidine, and MDA type compounds. Current activities also include presentation of training and the preparation of recipe file and estimate of yield databases.
An annual seminar is held each year during the week following Labor Day. Future seminars are scheduled for: Alexandria, VA (1996); San Diego, CA (1997); Little Rock, AR (1998); Toronto, Canada (1999); East coast of Australia (2000).
METHAMPHETAMINE, HYDRIODIC ACID AND EPHEDRINE TABLET EXTRACTION LAB SCENES ASSOCIATED WITH MEXICAN NATIONALS
Jerry Massetti, California Department of Justice, Fresno Regional Laboratory
Large Capacity clandestine methamphetamine laboratories associated with operatives from Mexico continue to inundate Central California. Work crews simulate agricultural processes to deliver, process and dispose of chemicals and equipment used to manufacture methamphetamine. An overview of these activities will be presented.
APPROACHES TO PROCESSING AND ANALYZING "MASON JAR" CLANDESTINE DRUG LABORATORIES
Pamela R. Smith, DEA Southwest Laboratory, National City, CA
Laboratory seizures of small amounts of liquid present particular analytical problems. Tips on handling techniques, extraction methods, and identification will be offered.
ION MOBILITY SPECTROMETRY: WHAT IS IT AND WHAT ARE ITS FORENSIC APPLICATIONS?
Pamela R. Smith, DEA Southwest Laboratory, National City, CA
Ion Mobility spectrometry (lMS) is an invaluable technique for trace evidence analysis. Examples of its application to abandoned clandestine laboratory sites, contaminated clothing, and screening of tablets will be presented.
Harry Skinner, DEA Southwest Laboratory, National City, CA
A review of the principals of stereochemistry as they apply to clandestine laboratory analysis of phenethylamines.
ENHANCED FUEL CELL INSTRUMENTS ARE PROVING THEIR SUPERIORITY IN EVIDENTIAL BREATH ALCOHOL TESTING PROGRAMS
M.R. Forrester Intoximeters, Inc.
Infrared has been the dominant technology in breath alcohol testing since the mid 1980's. The primary level of interest was the 0.100% BAC. With the lowering of this level to 0.080 in traffic work, 0.040 and 0.020 under the Omnibus bill, and 0.020 to 0.000 in juvenile investigations, the infrared systems of today are being pushed beyond their performance capabilities. This is because of the instability of the filters used, the influence of interferants at low alcohol levels, and the electronic noise that most infrared instruments presently mask with elevated baselines.
Faster fuel cells and new electronic technology have made it possible to run an unlimited number of tests in a given time period with no significant sensitivity loss. Coupled with linear, specific and low cost instrumentation, our new system may well become the dominant technology in breath alcohol testing. Particulars of this new technology will be detailed in the body of this presentation, with references to independent studies.
THE POLLY KLAAS KIDNAPPING INVESTIGATION: FBI SAN FRANCISCO'S NEW "CHILD KIDNAPPING TASK FORCE"
Gordon G. Mc Neill, Supervisory Special Agent, Federal Bureau of Investigation
- The POLLY KLAAS case and its ongoing impact on law enforcement as to its response to future abductions.
- New State of California legislation as a direct result of the KLAAS case.
- Development and implementation of a new "Bay Area Child Abduction/Serial Killer Task Force."
- Ongoing development by FBI San Francisco and Bay Area police departments of an investigative guide and protocol entitled "Assessing the Child
- New national initiatives by the FBI in child abduction and serial killer cases as well as technological initiatives by the FBI Laboratory on DNA.
THE DRUG RECOGNITION EXPERT AS CRIME SCENE INVESTIGATOR
Thomas E. Page, Sergeant, Los Angeles Police Department, Officer-in-Charge, Drug Recognition Expert Unit
The crime scene in a routine Driving Under the Influence (DUI) of drugs incident is not the location where the suspect was arrested. It is also not the vehicle that the suspect was traveling in. In a routine DUI-drugs case, the crime scene is the individual. It is the individual suspect who has the evidence of the crime. Unlike other crime scenes that usually contain physical evidence, the evidence in a DUI-drugs case is fleeting. The DUI-drugs crime scene includes the signs and symptoms of drug influence, such as dilated pupils, elevated vital signs, impaired balance and coordination, and more. The Drug Recognition Expert (DRE) is the crime scene investigator in a DUI-drugs case. The DRE obtains evidence by using a twelve-step standardized and systematic procedure that assesses the suspect's eyes, vital signs, divided-attention abilities, and psychomotor skills. This procedure includes obtaining a blood or urine sample for toxicological analysis.
This presentation will provide the participants with an overview of the evidence and the procedures that a DRE obtains in DUI-drugs cases. These procedures are also applied in Health and Safety Code violation cases.
COMMUNICATION AND CRIMINALISTS
Pete Demetriou, KFWB News Radio
How do criminalists ensure that juries, the public, and the media understand the significance of what they bring to a trial? KFWB reporter Pete Demetriou, a renowned specialist in police and crime reporting in Los Angeles, looks at the Simpson case. Using his own insight and observations, as well as those of many other Simpson news reporters, Mr. Demetriou offers suggestions on how to avoid the disaster of a communications breakdown in the courtroom.
ALL IN A DAY'S WORK: AN ENTERTAINING LOOK AT SOME VERY INTERESTING CASES
Dean M. Gialamas, California Laboratory of Forensic Science
Most criminalists, especially those employed by governmental agencies, often work only on cases involving criminal matters. Cases do arise, though, where aspects of criminalistics are needed for civil litigation and private interests. Over the last few years, a number of very interesting cases have been encountered. This presentation will take an entertaining and somewhat educational look a few of these cases:
- Case #1: How did GSR get on the victim's hands? Can the "unanswerable" be answered?
- Case #2: Mishap in the Desert I: Which car killed the victim driver? The suspect vehicle approaching head-on, or the victim's own car?
- Case #3: Mishap in the Desert II: Not a "whodunit" but a "whatdunit."
- Case #4: Criminalists in the Church: Can criminalistics really work miracles?
COP KILLER BULLETS REVISITED
Paul M. Dougherty, DWM Laboratory, Ojai, CA
In the early 1980's much was made about handgun projectiles (bullets) that were designed to penetrate metal or armor. As a result, legislation was passed to restrict or outlaw this type of ammunition. Now new legislation is being proposed in this area. This paper will review what ammunition is involved, its effect, and how the legislation can be circumvented.
PERFORMANCE PARAMETERS OF A REFINED FLUORESCIN TECHNIQUE ON LATENT BLOOD STAINS
Robert Cheeseman, 4844 Camino Roberto, Bonita, CA 91902, 619-470-8787
A refined fluorescin technique which was introduced by this author at the 1994 October CAC Seminar in Pasadena generated numerous questions from the audience which were not definitively addressed at that time. This improved technique using fluorescin has the potential to supplant previous blood detection systems that are more investigative in nature and yield less value as evidence due to difficulties in documentation.
This technique now employed in San Diego has been a significant improvement in latent stain sensitivity, surpassing luminol for blood stain pattern preservation. Additionally, it has the advantage of yielding superior documentation by utilizing low levels of ambient light. The scope of its application has been broadened to include substrates which were thought to be unstable by other blood enhancement systems.
The enhanced performance parameters now include: latent bloodstain patterns on clothing that has been subjected to multiple washings; latent footwear prints in which size, directionality and other class characteristics may be documented even on carpeting. Other aspects of this technique's sensitivity relative to luminol and its interaction when augmented by or combined with luminol has been addressed (paper pending).
The accommodation of traditional serology tests with the application of this technique will be discussed, as well as the effects of fluorescin on PCR based DNA analysis.
DRUG TESTING PROCEDURES AND RESULTS
Kathleen Cassel, Ph.D., A.B.F.T., Smith Kline Beecham Clinical Laboratories
At SmithKline Beecham Clinical Laboratories (SBCL), testing for drugs of abuse is performed in 18 of 26 laboratories in the US. Over the last seven years, SBCL has tested for drugs in more than 16 million samples from American workers.
Employers support drug testing because they know that employees who use drugs are 2.5 times more likely to have absences of 8 days or more, 3.6 times more likely to injure themselves or another person in a workplace accident, 4 times more likely to be involved in job related deaths, 10 times more likely to be involved in employee theft, and they are 33% less productive. In 1987, only 21 % of employers subscribed to drug testing programs. In 1995, 78% of US companies use drug testing to select and monitor their workforce.
This presentation covers a brief review of the background of workplace drug testing, the currently accepted methodologies, and explanations addressing several FREQUENTLY ASKED QUESTIONS regarding test results. In 1994, the positive rate for pre-employment drug testing was 4%. Ten percent of the positive results were FOR CAUSE. Marijuana was confirmed for 50% of the positive cases, and cocaine was confirmed for 25%. The general workforce positive rate for 1994 was 8.6%. Safety/Transportation had a 3.5% positive rate.
PROFICIENCY TEST FALSE POSITIVES: A LACK OF CRITICAL THOUGHT
Ronald G. Nichols, Oakland Police Department Criminalistics Laboratory
Drug proficiency tests were surveyed in an attempt to determine the cause of false positive results. The results of the survey indicate that the primary cause was a lack of critical thought on the part of the respondent. The results of seventeen drug proficiency tests and surveys provided by CTS over an eight year period were evaluated. For each test, the number of false positives was determined as well as the relative frequency of various testing methods used by the respondents. False positives were classified as either incorrect identifications or instances in which additional compounds not present in the submitted sample were identified. False negatives which included non-identifications as well as any reported results with some level of uncertainty were not evaluated in this study. A total of sixty-three false positives were reported for an average rate of 2.6%. Of the sixty-three respondents responsible for false positives, none used two microcrystalline tests. Meanwhile, fifty-six of the sixty-three respondents utilized GC/MS, IR or a combination of the two in their analytical scheme. Further evaluation of the analytical schemes of those responsible for the false positives was performed in an attempt to determine whether the methods used were unreliable. This further evaluation demonstrated that it was not the methodology that caused the false positives but rather the lack of critical thought on the part of the analyst. Many examples of this are presented.
UNUSUAL PARTICLES FROM TWO HOMICIDE POST-MORTEM EXAMINATIONS
Wayne Moorehead, Orange County Sheriff-Coroner Department, Forensic Science Services
A homicide was committed with an arrow. At autopsy, small green particles, some adhering to fibers, were recovered from the wound by a criminalist and submitted to the trace evidence section. These particles and fibers were examined. Later, a "reference" arrow was obtained. The arrow was thought to be representative of the types of materials used in arrows today. Samples were taken of the green parts of the arrow: the paint; the fletching; and the nock. None of these samples were similar to those recovered at autopsy. At another autopsy, several weeks later, small green particles, some adhering to fibers, were recovered from a gunshot wound and submitted to the trace evidence section. While these particles were thought to resemble post blast smokeless gunpowder kernels, under the stereomicroscope they resembled the particles from the arrow homicide. Further tests were performed and a search of the Forensic Science Center was conducted for possible sources of the particles. Worn cleaning pads were the source of the particles and fibers at autopsy.
CAPILLARY GAS CHROMATOGRAPH CHARACTERIZATION AND CLASSIFICATION OF SOME HYDROCARBON SOLVENTS AND ALKYL GLYCOL ETHERS
W. Moorehead and T. Dickan, Orange County Sheriff-Coroner Department, Forensic Science Services
Examination of multitudes of petroleum products and non-petroleum products by capillary gas chromatography assists the fire debris analyst in ignitable liquid classification (Class 0 through 5 ASTM/ATF protocol). Reformulated petroleum stocks of hydrocarbon solvents, such as Super Hi Flash Naphtha, several VM&P Naphthas, Isopar M, Isoparaffin 370, Shell Sol 142 HT and 340 HT, and alkyl glycol ethers were obtained and characterized, then classified according to the ASTM/ATF protocol.
Analysis was performed on a Hewlett-Packard GC/MS with a 15m x 0.25mm diameter 08-1 column having a 0.25~m film thickness. Initial time and temperature were 2 minutes at 40°C, then ramped at 25°C/minute to 300°C for 2 minutes. This programming provides good resolution over the accelerant range. The NIST 75K library was useful in identifying specific peaks in the chromatograms.
The petroleum industry's trend toward using isoparaffin, norparaffin, cycloparaffin, and alkyl benzene solvents as starting solvents for a multitude of household, commercial, and industrial products may involve more use of the GC/MS in identifying ignitable liquids from fire debris extracts and of the fire investigator to determine the nature of the identified product present, i.e., intentional addition (gasoline in a kitchen) or innocent presence (degreasing solvent).