117th SEMI-ANNUAL SEMINAR (Spring 2011)
CALIFORNIA ASSOCIATION OF CRIMINALISTS
May 16-20, 2011
Queen Mary, Long Beach, California
THE MURDER OF LA COUNTY POLICE CAPTAIN SPARKES
Christina Gonzalez(1), J.J. Cavaleri(1), James Carroll(1) and Phillip R. Stirling(2)
(1) Los Angeles County Sheriff's Department Scientific Services Bureau; (2) Los Angeles County District Attorney's Office
On August 10, 2004, Captain Michael Sparkes of the Los Angeles County Office of Public Safety was shot and killed when he identified himself and attempted to take action against two suspects as they attempted to rob him while he was off duty. Captain Michael Sparkes was taking a predawn bike ride near his home in South Central Los Angeles when he was confronted by two gang members. One of the suspects was armed with a high powered rifle. Shots were exchanged between Captain Sparkes and the suspects. Despite being mortally wounded, Captain Sparkes was able to provide a description of the two suspects. The Captain was transported to Harbor General Hospital, which was a location he had been assigned to protect. Tragically, he succumbed to his wounds at the hospital. Fortunately, the exchange of gunfire provided a variety of strong associative evidence including ballistics, trace and DNA evidence.
VISUALIZING LATENT BLOOD AT CRIME SCENES USING A PROTOTYPE MID-IR IMAGING SYSTEM
Stephen I. Morgan, Michael I. Myrick*, Heather Brooke, Megan R. Baranowski, Jessica N. McCutcheon; Dept of Chemistry and Biochemistry, Univ. of South Carolina
Current visualization methods for blood and semen are not specific, require dark conditions, potentially contaminate the crime scene, and may not always be sensitive. High discriminating power is important at crime scenes so that time and resources of forensic investigators are not wasted on the collection and analysis of false positive samples. We have designed a prototype portable system based on mid-infrared (IR) diffuse reflectance for visualization of latent blood stains. Lock-in amplifier techniques are used to construct the contrast image of the scene on a pixel-by-pixel basis in realtime, using techniques designed to enhance visualization of blood. An infrared source (e.g., a small heating plate, glowbar, or space heater) is employed to illuminate a scene with IR light. Light reflected from the scene is employed to achieve imaging by chopping the light source and digitally processing each pixel by a lock-in amplifier approach, to produce an output that is proportional to contrast between stained and unstained regions. Factors involved in optimizing discrimination with optical filtering include, but are not limited to, the detector response, optical throughput of the system, optical properties of the samples, and optical properties of the materials for sensitizing films/filters. The infrared camera response is sensitized to spectral regions where blood components (e.g., proteins) show absorbance using a combinatorial simulation-driven design process that selects chemical filters to maximize discrimination between blood-stained and unstained surfaces.
This approach has produced acceptably high signal-tonoise ratios and enabled visualization of blood well below bOX dilutions with visible contrast, while providing discrimination against some substances reported to give false-positive response with other techniques. Besides being rapid, IR imaging for bloodstain detection offers advantages: examiners are not exposed to chemicals, the technique can be used indoors or outdoors under ambient light, patterns are not smeared, and stains are not diluted or altered by chemical reagents. Most importantly, sampling for potential blood stains can be limited to areas producing image contrast indicative of blood. We have concurrently conducted fundamental studies to advance the scientific basis, and our understanding of, infrared imaging for crime scene visualization. Although additional instrument development and validation is required to realize our goals, this work has opened novel and intriguing forensic applications for imaging based on diffuse reflectance in the mid-infrared region of the spectrum.
DENSITY DETERMINATION VIA MAGNETIC LEVITATION
Matthew R. Lockett(1), Katherine A. Mirica(1), Charles R. Mace(1), Robert Blackledge*, George Whitesides(1)
(1)Dept. of Chemistry and Chemical Biology, Harvard University
Density is one parameter that may be used to characterize a trace object. Although the formula for density (or specific gravity) is simply mass divided by volume, this is not so easily done for tiny, irregularly-shaped objects. In the past the density of small objects has been compared/determined using the sink/float method of Paul Kirk. When the tested objects suspended in a liquid medium neither rose to the surface nor sank to the bottom, their density was the same as the liquid. This could be a slow process as the liquid medium was gradually made less or more dense by the addition of drops of either a miscible heavier or lighter liquid followed by mixing. Once this equilibrium point had been reached, one could determine the density of the liquid and hence the density of the object by removing sufficient liquid to fill a previously weighed pychnometer and then weigh the now full pychnometer. One could then obtain an actual value of density that could be entered into a database.
This talk will introduce an entirely different method of obtaining density that is quick (just a few minutes), requires no expensive instrumentation (not even a source of electrical power), does not require highly-trained operators, does not destroy the sample, is readily calibrated with a series of density standards, provides values that can be entered into a searchable database, and that can distinguish between samples whose density differs by as little as 0.0002 g/cm3. The method is based on magnetic levitation (MagLev) and involves placing diamagnetic samples into a container filled with a paramagnetic fluid, which is then placed between two permanent magnets. The vertical position of the sample, in the presence of the magnetic field, correlates with density. The vertical position of the sample is independent of mass and/or volume, and thus eliminates the need for standardized sample sizes. Results will be shown from eleven different glitter samples, six different commercial smokeless gunpowder samples, and glitter particles extracted from a brand of commercial nail polish. And lastly, for any do-it-yourselfers in the audience, we will show you how to easily and inexpensively make your own MagLev (such a deal!).
FORENSIC DISCRIMINATION OF DYED TEXTILE FIBERS USING UV/VISIBLE MICROSPECTROPHOTOMETRY AND MICRO-EXTRACTION/LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY
Stephen I. Morgan, Oscar G. Cabrices, Scott J. Hoy, and, James E.Hendrix; Dept of Chemistry and Biochemistry, Univ. of South Carolina
Trace evidence has taken on a role of increasing importance in forensic investigations. The principle that "every contact leaves a trace" establishes the potential value of minute traces of evidence found at the crime scene, or found on a victim or suspect. Fiber evidence is class evidence (i.e., not unique), because many fibers from different sources could be indistinguishable. The discovery of a fiber and its identification as a particular fiber type (e.g., acrylic, cotton, nylon, polyester) may not, of itself, provide much support for a forensic investigation. The probative value of particular fibers found at a crime scene depends on their uniqueness relative to the background of fibers normally encountered at that location in the absence of the crime. What is often required is information that makes the trace evidence more specific and discriminating.
Our research has addressed the task of achieving greater discrimination between trace evidence fibers in two different ways: by the use of UV/visible absorbance and fluorescence microspectrophotometry (MSP), and by micro extraction/capillary electrophoresis (CE) and by CE/mass spectrometry (MS). In forensic fiber comparisons, when spectra of known and questioned fibers are consistent, the hypothesis that the fibers originate from a common source should not be rejected.
We have applied pattern recognition techniques to fiber spectra and found MSP to exhibit high discriminating ability for comparisons among different fibers. However, fibers dyed with different dye formulations can have similar color and spectra; MSP does not identify the dyes present and cannot guarantee chemical equivalence of two fibers. After extraction of dyes from a fiber, however, LC/MS can separate extracted dye components and provide semi-quantitative estimates of dye amounts as well as qualitative information to identify the dye present (via the molecular weight and mass spectra).
Although this approach is destructive to the sample, only an extremely small sample is required (~1-2 mm of a single 15 μm diameter fiber). Automated micro-extractions and CE offer analysis with %RSDs ranging from 5-25% and with limits of detection in the picogram range.
FORENSIC EXAMINATION OF CLOTHING
Jane Moira Taupin, Forensic Consultant Melbourne, Australia
Clothing items are part of everyday life and thus are one of the most commonly encountered exhibits in crimes of violence. The construction of clothing means that it can be a repository for a wide variety of useful information. Garments may retain various types of evidence that have been deposited onto them in a wide variety of ways, most importantly during the crime event, often for many years and even decades. Clothing items have most often been worn on the body and consequently special features need to be considered. The garment may have travelled from one scene to another, may not have been stationary during the commission of the crime, or may even have been worn by someone else prior to, or subsequent to, the crime. There may be damage associated with deposits and deposits associated with particular actions and movements. With the advent of DNA profiling and the analysis of 'wearer' DNA, clothing items hold even more evidential value. The examination of clothing may not only provide associative evidence with persons or locations, but also tell the examiner a "story" as to what happened during a crime event, similar to a crime scene reconstruction. In some cases, a garment or a series of garments may be considered a 'crime scene'.
This presentation will describe some important aspects of clothing examination and a preferred approach using the scientific method. One of the critical aspects of clothing examination is the observation or 'searching' process. Searching for evidence is more than looking for a target evidence type. Successful searching requires presumptions, expectations and preliminary hypotheses. If the search for evidence is also reduced to a 'screen' then one of the most important phases of clothing examination is also reduced in importance.
Qualified criteria in clothing examination will be described which include hypothesis testing and testing decisions that can withstand scrutiny. Knowledge of clothing construction is also desirable especially when examining trace evidence or clothing damage. A holistic approach to clothing examination will be discussed that considers all elements of evidence recovered from the clothing examination and the how and why of the relationships between that evidence. In this way, maximum evidential value may be obtained from clothing exhibits related to a crime.
CRIME SCENE EVIDENCE DYNAMICS
The following two cases were presented to me for reconstruction; both were looked at by publicly employed criminalists. They did not support the DA's theory in either case. An outside expert was employed by the DA. In the first case, a man was accused of shooting his wife. The prosecution expert said it was obvious that it was a homicide. The scene was confused by the movement of the body and the physical evidence. The second case was re-studied after 15 years. The DA decided to prosecute. The same outside expert was hired. He failed to note the evidence dynamics in the case and concluded that the position of the body was because the defendant held the victim in a wrestling hold while the other one shot the victim in the head twice. The defendant had studied martial arts.
VALIDATION OFF PERMA-GEL® FOR BALLISTIC TESTING
Joanna Law; Los Angeles Co. Sheriff's Dept. Scientific Services Bureau
The study of terminal ballistics plays a vital role in ammunition selection for law enforcement. In order to study ammunition performance, many bullet manufactures and law enforcement ballistics researchers have tested various human tissue simulants, such as paraffin, soap, wood, and clay. Among such simulants, it has been found that the 10% gelatin composed from organic swine matter and water displays characteristics that are most similar to human tissue when struck with projectiles of small firearms. However, the preparation of the 10% gelatin has varied among researchers as gelatin manufactures lacked to provide detailed instructions and research that has shown that the gelatin needs to be stored at 4°C for no more than 36 hours. Due to such limitations, many manufactures have advertised new ballistic tissue stimulants among these companies is PERMA-Gel®.
PERMA-Gel® claims to have developed a ballistic gelatin that not only has the ability to be stored at room temperature for a limited amount of shelf time, it can also be reused up to fifteen times and is also more elastic in nature, mimicking the human tissue's elasticity much more than the traditional
10% ballistic gelatin.
In this study, the claims made by PERMA-Gel® will be validated by comparing the results of terminal ballistics of PERMA-Gel® to that of the 10% ballistic gelatin. Penetration and bullet diameter after impact of 9mm Speer Gold-Dot ammunition shot from a Model 19 Glock were compared. It was found that the depth of penetration is much more with PERMA-Gel® than the 10% ballistic gelatin; however, this does not affect bullet expansion.
PERMA-Gel® was also much more transparent and elastic than the 10% ballistic gelatin, making it easier to visualize bullet performance. Discoloration of the PERMA-Gel® gelatin is associated with overheating during the re-melting procedure, and even then it is still much easier to visualize bullet performance, when compared to the 10% ordnance gelatin. Despite over heating during re-melting, PERMA-Gel® was still reusable up to ten times.
The second focus of this study is to determine if PERMAGel® can be used to study what happens to a hollow-point bullet when shot through several layers of clothing mimicking what a human target might be wearing. Using the same ammunition and gun as in the first part of the study, one block of PERMAGel® was placed in contact with a couple of layers of denim, a layer of sweat shirt material and cotton. It was found that that the hollow-point bullet nose became clogged with the fabric as it passed through the gelatin obtaining the flight characteristics of a full metal jacket or a round nosed lead bullet. Due to the results in this study, PERMA-Gel® is deemed a valid gelatin for ballistic studies.
THE FORENSIC SCIENCE SOCIETY AS A PROFESSIONAL BODY
Dr. Carol Ostell; CEO Forensic Science Society, North Yorkshire, UK
I will aim to discuss what is meant by a professional body and how the Forensic Science Society has progressed since becoming a professional body in 2004. The contribution of the Society to quality standards and its impact in the educational arena will be detailed. Recent developments in regard to the introduction of chartered status and the Forensic Science Society Register of Chartered Forensic Practitioners will also be covered. Finally, the importance of collaborative and partnership, working our representation on national committees and contribution to debates will draw the presentation to a close.
THE CONFOCAL MICROSCOPY ANALYSIS OF TEN CONSECUTIVELY MANUFACTURED RUGER P95 BREECH FACES
Todd Weller; Oakland Police Dept. Crime Laboratory
This presentation will show the results of confocal microscopy analysis often consecutively manufactured pistol slides. Confocal microscopy allows one to collect and numerically record, three-dimensional topography. The purpose of this study was to use this technique to study test fires recovered from pistols with consecutively manufactured breech faces. This study provides numerical, objective validation that consecutively manufactured firearms can be distinguished from each other using the marks left on fired cartridge casings. Additionally, this study provides objective validation that cartridge cases can be associated to a firearm through the comparison of these same markings.
THE JASMINE FIORE HOMICIDE
Jeanne Putinier; Orange County Sheriff-Coroner Department Crime Lab
On the morning of August 15, 2009, the nude and mutilated body of a female was discovered in a suitcase inside a dumpster at an apartment complex in the city of Buena Park, CA. The body was later identified as that of swimsuit model Jasmine Fiore based on the serial numbers associated with her breast implants. The case gained international attention when it was discovered that reality TV personality and Canadian citizen, Ryan Jenkins, was the prime suspect. The search for evidence (and Jenkins) led Buena Park Police detectives from San Diego, CA to Blame, WA, where Jenkins was able to escape to Canada on his boat. Jenkins was discovered by Canadian authorities after taking his own life in the hotel where he was hiding.
Details of the crime scene investigation, autopsy, vehicle examination, and police investigation will be presented along with the results of toolmark and trace evidence examinations of Fiore's remains, toxicology findings, and DNA analysis.
QA AND ISO ROUNDTABLE DISCUSSION
Karla Taylora(1), Pennie Laferty(2), Jan Jones(2), Jasmine Jefferson(3);
(1) Los Angeles Co. Sheriff's Dept. Scientific Services Bureau; (2) Orange County Sheriff-Coroner Department Crime Lab, (3) Long Beach PD
This presentation is designed to allow the attendees to ask questions about Quality Assurance in general as well as specific questions about ISO 17025 Accreditation. There will be three members on the panel with varying levels of experience with the ISO process. The transition to ISO 17025 seems to be an overwhelming task at the beginning. It our hope that being able to ask questions of colleagues who are going though the process, or who have completed it, will help others with practical advice to address their concerns.
EVALUATING KNIFE EVIDENCE FOR DNA
David Jackson; San Francisco Police Department Criminalistics Laboratory
Knives, or similar weapons that are used in stabbing events, may not show the presence of blood or tissue on obvious surfaces such as the blade, and in many cases may need to be dismantled to expose other surfaces containing possible blood or tissue. Stab wounds of solid organs may result in the absence of blood because the pressure of the knife prevents bleeding.
The SFPD Criminalistics Lab has documented the results from several cases involving knife blades that show negative results for blood upon the initial visual examination, and initial chemical presumptive blood testing, even when multiple stab wounds are reported. However, in subsequent DNA typing. the SFPD Criminalistics Lab has developed single source DNA profiles from such cases. In one knife case, during microscopic examination, possible opaque tissue was observed and may be attributed to the adipose tissue of the victims' torso. Dismantling techniques of various types of knives has also provided biological material proven to be the key investigative lead in several other cases. In particular, the examination of concealed portions of box cutter blades, knife blades, and internal surfaces of knife handles has led to the recovery of probative DNA profiles, even when biological screening has yielded negative results.
It is our conclusion, supported by documented casework experience and medical reference material, that implements used in stabbing events may, on a regular basis, show no, or discreet signs of the presence of blood or tissue but could yield a probative DNA profile. Therefore, these items should be subjected to the DNA typing procedure. The lack of blood evidence on such implements should not solely be regarded as an indication not to progress with genetic analysis. The various casework approaches that have been adopted and documented by SFPD criminalists involving the biological screening and subsequent DNA analysis of knives will be presented.
SCIENTIFIC EVIDENCE IN THE COURTROOM
Tracy Lopez; Los Angeles Co. District Attorney's Office
A discussion of current legal topics of interest to criminalists, including the impact of Melendez-Diaz v. Massachusetts (2009) 129 S.Ct. 2527, and other cases regarding scientific evidence which are also pending before the Supreme Court.
The presentation will also include common courtroom issues, including discovery, which arise in typical criminal cases which employ scientific evidence.
ENABLING EXTRACTION-FREE PROCESSING OF REFERENCE SAMPLES
Andrea Carbonaro*, Dennis Wang, Chan Zhong, Mary Ma, Lisa Calandro, Lori Henessy; Life Technologies
Laboratories worldwide are developing or expanding forensic DNA databases and are looking for simple, robust, high throughput workflows to efficiently process their single source samples. Direct amplification from blood or buccal cell samples deposited onto FTA® cards is routinely being done using the AmpFlSTR® ldentifiler® Direct PCR Amplification Kit. To further expand the direct amplification workflow to samples deposited on non-FTA® substrates, we have developed a lysis buffer to simplify the upstream sample preparation protocols. The lysis buffer chemistry eliminates any incubation or heating steps and generates STR profiles of higher quality as compared to other on-market lysis protocols for the direct amplification workflow. Addition of 1.2 mm punches to the lysis buffer from buccal samples collected on the Bode DNA CollectorTM or a sampling of cellular material collected from swabs added to the lysis buffer yielded results comparable to profiles obtained with samples on FTA® cards. Results from external testing of the lysis buffer using the ldentifiler® Direct kit showed a >90% first pass success rate using a peak amplitude threshold of 50 rfu. Quality STR profiles were obtained with the average intralocus balance at >65% and the average intracolor balance at >40%. Comparative studies were performed to demonstrate that the new lysis chemistry and workflow generated higher first pass success rates and better data quality over other current on-market lysis protocols for the direct amplification workflow. The lysis buffer effectively enables direct amplification for samples on non-FTA® substrates. Additional experiments demonstrate an improvement in profile quality using the lysis buffer for direct amplification in conjunction with the AmpFlSTR® NGMTM and NGM SElectTM PCR Amplification kits.
IMPROPER ARSON PACKAGING AND ITS ABILITY TO RETAIN IGNITABLE LIQUIDS
Eric Wahoske; Los Angeles Co. Sheriff's Dept. Scientific Services Bureau
There is a large amount of literature covering the correct packaging of fife debris evidence. The literature does a good job at showing how fire debris should be packaged, but there are deficiencies in the research regarding improper packaging material such as polyethylene bags.
Occasionally improperly packaged fire debris evidence is submitted for analysis, and the analyst must be aware of any deleterious effects resulting from the packing material. While polyethylene bags and regular Kapak bags (not FirePak) may not be the best bags for fire debris evidence, each was examined for its ability to retain ignitable liquids and deter cross contamination.
The study showed that regular heat sealed Kapak bags did a good job at retaining ignitable liquids while heat sealed polyethylene bags were extremely permeable to ignitable liquids.
FORENSIC SCIENCE IN VIOLENT CRIME INVESTIGATIONS
lgnacin Quinones(1), Denise Syndercombe-Court(2), and Barbara Daniel(2)
(1) Dept. of Forensic Science and Drug Monitoring, Kogn's College, London; (2) Blizard Inst. of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry
To combat violent crime, police forces have turned to DNA profiling as recent advances have enabled the use of minute traces of biological material, such as fingerprints, to be used a source of DNA. This investigation aimed to improve our understanding of how DNA is deposited through touch and to explore relevant applications for use in the criminal justice framework.
The results have shown that sloughed skin cells yield no DNA and that touch DNA comes from either the transfer of nucleated cells from elsewhere (eyes; mouth) or as cell free DNA exuded in sweat. The amount of DNA deposited is highly variable both between and within individuals. DNA extraction methods that ensure both cellular and non-cellular DNA is recovered maximise the potential for DNA profiling. It is postulated that in hand to hand fighting, DNA may be recovered from clothing.
In a collaborative study with Joanna Fraser, from the University of Avertay, Dundee, we used vacuum metal deposition to locate hand marks and followed this with localized extraction to maximise DNA recovery.
POLYTHINKING: DOES IT STILL HAVE A PLACE AND A CHANCE IN THE MODERN CRIME LAB?
Lucien Haag; Forensic Science Service - Carefree, AZ
This Officer-Involved Shooting (OIS) incident was witnessed by multiple individuals each of whom had a different account of the events immediately prior to and during the fatal shooting of a subject. These accounts also differed from that of the shooter. If we still believe as Kirk once said that reconstruction is the ultimate goal of criminalistics, then at the very onset of our involvement in the case, we need to know the context of the case and employ "polythinking". Polythinking requires a thoughtful selection of the appropriate tests and a sequence of these tests to properly evaluate the accounts of the witnesses and shooter with the multiple goals of eliminating the impossible or improbable and either establishing the probable, or ideally establishing those matters that are certain. Polythinking is the antithesis of following rote, standard protocols dictated by some laboratory procedures manual. But what if there is no validated procedure in the laboratory's procedures manual for one or more tests that are deemed necessary to answer certain questions in the case? Must analytical thinking stop and the pursuit of true criminalistics end? After a brief presentation of the alleged events of this shooting, the attendees will be asked to think and contemplate what tests, and in what order would they be done. Who will conduct these tests and can the laboratory carry out a test for which there is no validated procedure in its procedures manual? The observations and tests carried out by the author along with a summary of the initial laboratory findings of others will conclude this presentation.
CSI SCHOOL KIDS: LESSONS LEARNED IN PRODUCT DEVELOPMENT FROM THE CLASSROOM TO THE CRIME SCENE
Philip Morton* BSc.(1) and Professor John P. Cassella FFSSoc(2)
(1) Product Development Manager, SciChem International, Research Fellow, Staffordshire Univ., UK; (2) Department of Forensic Science and Crime Science, Faculty, Staffordshire Univ., UK
This presentation will summarise the achievements of a two year 'Knowledge Transfer Partnership' (KTP). The KTP was funded by regional governmental funding, and was a collaboration between forensic science academia at Staffordshire University and SciChem International, a commercial company in the Midlands. Initially tasked with producing a series of 'Forensic Investigation' classroom activity kits, the KTP created a new department within the company which now designs, develops and produces science-based resources covering a broad range of science applications for learning and teaching. The product development process, developed as part of the KTP, enables fast, reliable resource development. This innovative process was awarded the prestigious "Lord Stafford Award for Innovation Achieved" in 2010. Alongside the development of physical resources, techniques were developed for teaching pupils of all ages, key practical skills in forensic science. These techniques have been delivered in literally thousands of school classrooms over the last two years, discounting popular 'CSI-Effect' myths, and educating the UK juries of the future. This project between commerce and academia has successfully and robustly developed forensic science resources for both 'Higher' and 'Further' education levels within the UK. A high quality, low cost apparatus for training and research has been developed within this project and this has demonstrated that there is opportunity for innovation in the 'low-tech' side of the forensic science supplies market. Previews will be shown of upcoming resources for several different forensic disciplines.
THE STATISTICAL EVALUATION OF TORN AND CUT DUCT TAPE PHYSICAL END MATCHING
Kaitlin McCabe; Univ. of California, Davis
Duct tape is often found in association with criminal activity, most commonly in abductions, homicides, and the construction of explosive devices. As such, forensic scientists are frequently asked to analyze and compare duct tape samples in order to establish possible evidentiary links between a suspect and victim, a suspect and a particular crime, or multiple crimes. Through duct tape end matching, analysts can reunite separated fragments. Based on the principle that each tear is unique, this type of matching has a significantly high evidentiary value and is considered to be one of the strongest associations in forensic science comparative examinations. Physical end matching of duct tape is common in crime laboratories, yet the process of physical end matching remains undefined and the reliability and error rates associated with these generally accepted procedures are unknown.
This study was designed to research duct tape physical end matching through an examination of criteria to describe the matching process, development of a protocol for training analysts in physical end matching, and statistical evaluation of the associated error rates and overall accuracy. Each trial evaluated the variation in inconclusive rates, error rates, and accuracy rates due to: differing brands, grades, and colors of duct tape; differing analysts; and differing separation methods. In addition, the design also helped to assess the reliability of the protocol through the reproducibility of the end results provided by blind peer review, as well as allow assessment of conditions that could restrict its validity.
The experimental design consisted of a blind study looking at four different methods of separating duct tape: hand torn, Elmendorf machine torn, scissor cut, and box cutter knife cut. Three Graduate Student Researchers (GSRs) were selected to work as duct tape analysts for the entire study. The GSRs produced individual results from the same sets, and the possible outcomes of a hypothetical peer review between analysts was assessed.
This study confirms that it is possible to use physical end matching to identify duct tape samples as matching or non-matching and that differences between analysts, brands, tape grades, tape color, and method of separation have varying contributions to misidentifications or inconclusive results. This research looked at 1800 torn tape specimens and 400 cut tape specimens. Overall, it seems that the brand and tape grade are more important than color in their effect on an analyst's ability to correctly identify duct tape end matches. Scissor cut tapes appear more difficult to analyze than hand torn tapes, but there is no significant difference in difficulty between hand torn tape and tape cut with a box cutter knife. Finally, consistent tearing conditions do not seem to affect an analyst's ability to correctly identify duct tape end matches.
This study also demonstrated the importance of peer review in duct tape analysis and its ability to greatly reduce the number of misidentifications made by analysts.
Malt Murphy(1) and Gina Satriano(2)
(1) Orange Co. District Attorney's Office; (2) Los Angeles Co. District Attorney's Office
For a decade, Rodney James Alcala deceived everyone, law enforcement and mental health professionals included, with regard to his narcissistic and sexually sadist nature. For three decades, he eluded the justice system with respect to the extent of his criminally sexually violent conduct. Forensic science and the development of DNA technology eventually caught up with Rodney Alcala's over 10-year devastation of lives.
From 1968-1979 he was involved in the solicitation of teenage girls, the brutally violent sexual assault of 8 and 15 year-old girls, the kidnap and torture murder of a 12 year-old girl, and the brutal sexual assault torture murders of four adult women. Justice for these acts was not ultimately realized until 30 years later.
During a unique joint county prosecution between the Orange County and Los Angeles County District Attorney's Offices, Rodney Alcala represented himself at trial. He cross-examined his live victims and the family members of his murder victims. He was convicted of five murders and sentenced to death. This result is primarily due to the forensic evidence analysis presented during trial which was performed by crime labs including the Los Angeles County Sheriffs Department, the Los Angeles Police Department, the Orange County Sheriffs Coroner Department, and private crime labs.
THE EFFECT OF SUBSTRATE ON THE ANALYSIS OF IGNITABLE LIQUIDS
Christopher Dal Chele; Calif State University, Los Angeles
The analysis of ignitable liquids is a well documented and researched field of forensic science. Various patterns and identification techniques have been established in an attempt to detect a variety of ignitable liquids. These patterns are dependent on various characteristics of the liquid in question; the amount present, the temperature or climate it has been exposed to, how long it has been allowed to evaporate, and many more.
One key attribute that can influence the pattern observed is the substrate the ignitable liquid is present on. Utilizing well established PHCE techniques with activated charcoal, the relationship between the pattern that is observed on a chromatogram and the effect the substrate has is analyzed. It is found that the pattern can be significantly changed when the substrate is a plush analogue of a stuffed animal. Additionally, there is also an observable effect when the analogue of an automotive seat is analyzed.
DETERMINING THE TIME OF DEPOSITION OF A BLOODSTAIN USING UV-V1S SPECTROPHOTOMETERY
Catherine Aldorisio*, Katherine A. Roberts, Donald J. Johnson; Calif State University, Los Angeles
Recent scientific advances have allowed forensic biologists to obtain a wealth of information from bloodstains deposited at a crime scene. Conventional serology can confirm that the stain is blood; immunoassays can determine whether the source is human or animal; while STR-based DNA typing can provide a STR profile from the bloodstain, which includes information on whether the donor is a male or female. However, at the present time, one crucial piece of information eludes criminalists. Currently, no method exists to reliably estimate the time of deposition of the bloodstain. This information could be very useful for investigators, as it would indicate whether or not the bloodstain is relevant to their case. For example, determining the time of deposition would help address the question of whether the stain was deposited during the commission of the crime or if it pre-existed the event. Hanson and Ballantyne (2010) conducted a study that proposes the use of ultraviolet-visual (UV-VIS) spectroscopy as a reliable method for determining the time since deposition (TSD) of a dried bloodstain. This method was found to have high resolving power and was demonstrated to distinguish between bloodstains that were deposited minutes, hours, days, and weeks prior to analysis. The method analyzes the Soret band (lmax =412nm) of hemoglobin; as the bloodstain ages the Soret band appears to undergo a "blue shift" to a shorter wavelength. The authors also found that the extent to which the shift occurred was related to the environmental conditions (temperature and humidity) during storage.
The purpose of the study proposed here is to further validate the use of UV-VIS as a reliable method for determining the time since deposition of a bloodstain. This study will focus on the use of a portable spectrophotometer (NanoPhotometerTM Implen, Inc., LABREPCO, Horsman, PA), to evaluate its usefulness in field investigations. The focus of the study will be to determine the time since deposition (TSD) of a bloodstain by measuring the UV-visible spectrum of hemoglobin (dependent variable). The following four independent variables will be evaluated in order to measure their effect on the UV-visible spectrum of hemoglobin: Time since deposition (TSD), temperature, % relative humidity, and substrate used to deposit the bloodstain.
RECOVERY OF DNA FROM THE INTERIOR OF FOOTWEAR AND GLOVES
Maryam Nickooshiam, Katherine A. Roberts and Donald J. Johnson; School of Criminal Justice and Criminalistics, Calif. State Univ., Los Angeles
This study investigates the factors influencing the success of recovering DNA profiles from interior surfaces of footwear and gloves. Samples were tape lifted prior to DNA isolation and mitochondrial and nuclear DNA analysis. Overall, gloves yielded fewer DNA profiles when compared to footwear. A higher number of full mtDNA profiles were obtained from items that were older, were less-frequently used, and had a shorter time elapsed between the last use and sampling. A comparison of typing methods demonstrated that mtDNA typing appears to be more sensitive and can successfully genotype samples containing low levels of nuclear DNA.
This study was successful in recovering mtDNA and STR profiles from interior surfaces of footwear and gloves using tape lifting as a sampling method. Thus, DNA obtained from such items may be used by investigators to associate the perpetrator to the item and or crime scene when other methods prove inadequate.