120th SEMI-ANNUAL SEMINAR (Fall 2012)
CALIFORNIA ASSOCIATION OF CRIMINALISTS
November 5-9, 2012
San Jose, California
FINGERPRINTS FOREVER - VISUALIZING FINGERPRINT CORROSION OF METALS
Dr. John Bond, University of Leicester
The visualization of fingerprints on metal surfaces after the metal has been subjected to environmental extremes is discussed. Visualization is achieved by exploiting the natural chemical reaction that can occur between the metal surface and fingerprint sweat deposit. This reaction, effectively a corrosion of the metal surface, can result in a change to both the chemical and physical characteristics of the metal surface. We show how visualization can be achieved by various methods including optical interference, digital color mapping and electrostatic attraction. We demonstrate how fingerprints deposited on brass cartridge cases pre-firing can be visualized post-firing and examples are given from homicides where this technique has been employed. More recent application to improvised explosive devices (IED) is also discussed.
THE FUTURE OF CRIMINALISTICS - RESTORING SCIENCE
Peter R. De Forest, Professor Emeritus, John Jay College of Criminal Justice/ CUNY; Gregory B. Matheson, Laboratory Director, Retired, Los Angeles Police Department
It would not be an exaggeration to assert that criminalistics is the last, best hope for fair and effective criminal investigations. No other source of information (e.g., eyewitnesses, complainant statements, interrogation, confessions, etc.) in a criminal investigation can approach the veracity and potential effectiveness of a complete and detailed understanding of the physical evidence record. There is nothing potentially more powerful. Nothing else even comes close. Extracting information from and interpreting the physical evidence record is the job of scientists and lies within the realm of criminalistics. Sadly, although no other avenue of investigation offers more promise, this promise is not realized in practice. There are several reasons for this. For one, scientists (read criminalists) don't have oversight and control over the entire process of the recognition and extraction of information from the physical event record. Although there are no immediate solutions, and there is considerable inertia built into the system, these adverse factors or impediments need to be recognized and dealt with. Many of these cannot be directly addressed by the working criminalist. However, this is where the effort to bring about change should begin.
Well-intentioned policies and criticism by well-meaning outsiders have led to improvements in our field, but they have also contributed to impediments to the realization of the ideal. Accreditation and outside criticism premised on the misconception that forensic science laboratories are nothing more than testing facilities falls short of addressing our problems.
There is much more to criminalistics than simply testing evidence where the problem is circumscribed and defined by a nonscientist. The best case solutions don't flow from inquiries constrained in this way. Far from it.
The disparity between the potential of criminalistics and the reality in practice is frustrating for many criminalists. What should be an intellectually rewarding career can be thwarted by well-intentioned concerns that are misdirected or misapplied. Case solutions can also be adversely affected in profound ways. One example is accreditation. Accreditation has brought about many positive changes in the field, but this has not come about without unintended adverse consequences.
Bob Blackledge shared an e-mail note that he received from one criminalist. This was prompted by an e-mail that Bob sent to a CAC trace evidence group suggesting that the members might find a photomicrographic attachment to a mobile phone useful for some physical evidence documentation. He did not share the identity of the correspondent. The quote follows:
Thanks, I will definitely take the time to check it out. Although, in light of ASCLD/ISO, I would likely not be allowed to use it for anything work related because....I don't have the proper certificate of training, or its not work issued, or on a secure network, or I haven't been proficiency tested on its use....and so on! I agree there should be training and guidelines, but we seem to able to use our brains less and less these days. Common sense isn't allowed anymore. It seems we are able to say less even with more technology.
This criminalist's concern is undoubtedly shared by others and should be disturbing to all of us. It should not be ignored. Since the correspondent is not known to us, we cannot determine whether to ascribe this view to experience with the misapplication of ASCLD/LAB ISO guidelines by laboratory management, or to perceptions on the part of the author of the e-mail note, or a combination of both.
Ideally, criminalistics is potentially one of those rare careers where one can find it to be demanding intellectually, crucially significant for society, and personally very satisfying. What can be done to restore this potential?
It is hoped that this presentation will generate considerable discussion and result in the formulation of initial plans of action.
REVIEW OF 3D ANALYSIS IN FIREARM AND TOOL MARK IDENTIFICATION
Todd Weller, Oakland PD Crime Laboratory
Firearm and tool mark identification has seen a number of admissibility challenges in the past several years. The challenges include criticism that firearm and tool mark identification is not objective, is not scientific, and that the fundamental concepts have not been properly tested. Recent scientific studies that combine the capture of three- dimensional topography and mathematical analysis provide strong evidence that these critiques are wrong. This presentation will highlight some of the recent studies and how they provide objective, scientific support that the discipline of firearm and tool mark identification is on solid a foundation.
THE WITNESS EXECUTION OF TONG VAN LE
Eric Halsing, Jan Bashinski CA DOJ DNA Laboratory
In August of 2008, Tong Van Le assisted the San Francisco Police in identifying the two young men who he claimed robbed his liquor store at gunpoint. Three weeks later, on September 13, he was killed while pulling into his garage in a quiet Marin County neighborhood. A fast-paced investigation took place between the Novato and San Francisco Police Departments. On September 16, evidence began arriving at the laboratory and I was assigned to the case. In the days and months that followed, the Police and DAs Office working together with the California DOJ Bureau of Forensic Services, would piece together a case against six defendants. This talk will describe the crime, the evidence that was submitted to me for DNA testing, my results, the excellent work of the other forensic examiners involved, the trial which lasted more than six months, and the ultimate outcome of the case against the defendants.
FOUNDER'S LECTURE: THE CHALLENGE OF ACADEMIC FORENSIC SCIENCE: PAST, PRESENT, AND FUTURE
Dr. George Sensabaugh, UC Berkeley
NATIONAL SCIENCE AND TECHNOLOGY COUNCIL (NSTC) COMMITTEE SUBCOMMITTEE ON FORENSIC SCIENCE REPORT
Mark Stolorow; NIST
In 2009, the White House Office of Science and Technology Policy (OSTP) coordinated the establishment of a Subcommittee on Forensic (SoFS), to assess and enrich the state of forensic sciences in the United States. The purpose of the Subcommittee is to advise and assist the Committee on Science, National Science and Technology Council, and other coordination bodies of the Executive Office of the President on policies, procedures, and plans related to forensic science at the local, state and federal levels.
Over the last three years, The Subcommittee's activity was organized through five interagency working groups (IWGs):
- Research, Development, Testing, and Evaluation
- Standards, Practices and Protocols
- Education, Ethics, and Terminology
- Accreditation and Certification
- Outreach and Communication
The SoFS is scheduled to sunset on December 31, 2012. This presentation will provide insight into some of the important issues that have been considered through the interagency process to include mandatory accreditation, certification, proficiency testing, terminology, AFIS interoperability, and forensic science R&D.
MORE THAN JUST STANDARDS: NIST LAW ENFORCEMENT STANDARDS OFFICE FORENSIC SCIENCE PROGRAM UPDATE
John Paul Jones II; NIST
A recent survey revealed crime laboratory management is familiar with standard reference materials produced by the National Institute of Standards and Technology (NIST), such as the Human DNA Quantitation Standard. Yet there is so much more activity taking place on the NIST campus than standards creation. The Forensic Science Program (FSP) at the Law Enforcement Standards Office (OLES) within NIST conducts and coordinates research and provides technical services to address the needs of the forensic science community. The FSP focuses on creating new material standards; initiating metrology research; evaluating technologies; and establishing expert working groups to facilitate knowledge exchange and identify best practices. These activities have been used to support forensic science disciplines such as: arson; digital and multimedia forensics; DNA; fingerprints; firearms and toolmarks; odontology; controlled and dangerous substances; toxicology and trace analysis. A high level description of many of NIST's ongoing forensic science projects will be presented which includes:
- Expert Working Group on Human Factors in Latent Print Analysis
- Personnel Selection Tool for Latent Prints
- Expert Working Group on the Preservation of Biological Evidence
- 3D Topography Correlations of Bullets and Casings
- Photo scales and Forensic Photogrammetry
- Computer Forensics
- NIST OLES's Research on the Scientific Working Groups
- Upcoming publications
NEW BIOLOGICAL EVIDENCE TRAINING FOR INVESTIGATIONS
Bonnie Cheng; Oakland PD Crime Laboratory
Biological evidence has played a major role in solving cold cases, identifying missing persons or unknown individuals, and providing leads in homicide, sexual assault, and burglary cases. Crime scene investigators, criminal investigators, and district attorney investigators each play a vital role in the collection of biological evidence recovered in a criminal case. These different investigative units are often compartmentalized and the investigators are not aware of the upstream or downstream role biological evidence plays in the overall investigation.
Techniques in the collection and processing of DNA evidence are advancing at a tremendous rate. Law enforcement personnel need to be constantly enlightened to these advances; however, a gap exists in training for law enforcement personnel who come into contact with or utilizes biological and DNA evidence as a tool during the investigation of a case.
DNA Evidence for Investigators is a course developed with input from DNA analysts, district attorneys, crime scene personnel, and police officers on how to train criminal investigators on effective DNA uses. The purpose of this course is to close the gap by teaching investigators what, why, and how evidence is processed from various criminal incidences (i.e. homicides, sexual assaults, burglaries, robberies) and how to more effectively use the laboratory analysis to further their investigation. This 24-hour interactive course addresses the role biological evidence plays in a criminal investigation from crime scene to adjudication.
EXPLORING THE CAPABILITIES OF MIXTURE INTERPRETATION USING THE TRUE ALLELE SOFTWARE
Michael D. Coble and John M. Butler
DNA mixtures from sexual assault evidence or high volume crimes such as burglaries can be challenging for the forensic scientist to interpret. The problem is exacerbated when the evidence contains more than two contributors or is highly compromised due to DNA degradation. Guidelines for mixture interpretation developed by Clayton et al. (1998) have been widely accepted and serve as a logical step-wise model to interpret mixtures.
Laboratories have developed "in-house" spreadsheets or have purchased commercial software to rapidly calculate the multiple parameters necessary for mixture interpretation using the Clayton et al. method (e.g. peak height ratio, mixture ratio, etc.). Additionally, mixture software can be used to calculate statistics using either Random Man Not Excluded (e.g., combined probability of inclusion, CPI) or Combined Likelihood Ratio (CLR) to evaluate the data.
We have evaluated the True Allele Software (CyberGenetics, Pittsburgh, PA, USA) by analyzing an assortment of two-, three-, and four-person mixtures. The software uses quantitative probabilistic genotype modeling of the data to form a joint LR statistic for the weight of the evidence. We examined a series of controlled two-person mixtures with differing contributor ratios and a broad range of allele sharing between the samples to determine the efficacy and reproducibility of the software. For complex mixtures, we examined the gain in information (measured by the log LR) compared to data evaluated with CPI and CLR statistics.
THE ROLE OF NEXT GENERATION DNA SEQUENCING IN FORENSIC mtDNA ANALYSIS
Dr. Mitchell Holland, Penn State University
Current practices for performing forensic mitochondrial DNA (mtDNA) sequence analysis, as employed in public and private laboratories across the United States, have changed remarkably little over the past 20 years. Alternative approaches such as next-generation sequencing, have been developed and proposed, and these new technologies have the potential to streamline the testing process, interpret heteroplasmy, and deconvolute mixed mtDNA profiles. The role of these NGS methods, laboratory experience and results in forensic mtDNA analysis will be discussed. *Note, abstract taken in part from http://www.mitotyping.com/mitotyping/lib/mitotyping/FSR_Paper,_2012-2.pdf
WHOLE MITOCHONDRIAL GENOME SEQUENCING USING PROBE CAPTURE AND 454 NEXT GENERATION SEQUENCING
Valerie McClain; University of California, Davis; Children's Hospital Oakland Research Institute
Cassandra Calloway; Children's Hospital Oakland Research Institute
George Sensabaugh; University of California, Berkeley, Berkeley, California
Next-generation sequencing (NGS) technologies are emerging as powerful tools for biomedical research and clinical applications and have the potential to revolutionize forensic DNA analysis. NGS technologies are characterized by parallel determination of hundreds of thousands to millions of short sequence reads (100-500 bp) in a single run. NGS can be used for direct sequencing of DNA products generated by PCR, of DNA fragments generated from intact DNA, or of DNA fragments occurring as a consequence of environment degradation. Of the several NGS technologies are available, the 454 sequencing technology currently appears to be the most suitable for forensic applications because it can directly sequence 400-500 bp lengths of DNA. The 454 Genome Sequencer is a scalable, highly parallel pyrosequencing system that uses emulsion- based PCR for 'clonal' amplification of single DNA sequences. The 'clonal sequencing' aspect of this technology allows both sequencing of DNA present in very low quantity and quantitative detection of variants present in less than 1% in a mixture.
Mitochondrial DNA (mtDNA) sequence analysis is of proven value in forensic cases where samples are degraded and nuclear STR testing cannot produce a complete discriminating profile. A central technical challenge in forensic mtDNA analysis is to selectively generate mtDNA sequences from samples containing a preponderance of nuclear genomic DNA. The standard approach is to selectively amplify mtDNA sequence regions of interest which are then directly sequenced, whether by conventional Sanger sequencing or more recently by NGS.
We describe here a novel alternative approach to mitochondrial DNA (mtDNA) sequence analysis by NGS which employs a liquid phase hybridization probe capture system to selectively capture mtDNA fragments from whole genome DNA samples. We use the Nimblegen SeqCap EZ platform due to its extensive tiling design and ability to efficiently synthesize hundreds of thousands of probes. To increase the specificity of our probes, we considered the circular nature of mtDNA, the high density and distribution of sequence polymorphisms, and nuclear pseudogenes in our probe design strategy. Our final design covers 99.9% of the mitochondrial genome with unique probes. For the NGS, we use the 454 NGS platform due to the longer read length (~500bp) and the affordability of the 454 GS Junior system for forensic laboratories.
Our results show successful capture of 100% of the mitochondrial genome of all samples with coverage adequate to yield unambiguous sequence assignments with an average on target capture rate of 75%. Multiple samples have been tested to evaluate the specificity of our assay; all SNPs previously detected by Sanger sequencing were also detected by 454 sequencing. We have tested the sensitivity of our method by reducing the starting amount of DNA to forensically relevant DNA levels (<1ng sample DNA) with no loss in sequencing accuracy. Our method also achieved resolution of mixtures below the limits of Sanger sequencing (<10%). To improve efficiency, the probe capture hybridization time was reduced from the manufacturer's recommendation of three days to one day. This greatly improves the throughput of the capture method, without affecting the on target capture rate, or accuracy of the capture probes. In conclusion, we have successfully developed a method for whole mitochondrial genome capture followed by NGS which can be applied to the field of forensic science.
APPLICATIONS OF ION TORRENT PGMtrade; IN HUMAN IDENTIFICATION
Robert Lagacé, Sharon Chao Wootton, Reina Marie Langit, Walther Parson, Lori Hennessy, Life Technologies
The field of human identification has been dominated by capillary electrophoresis-based (CE) STR fragment analysis. There has also been a minor effort to sequence the hypervariable regions I/II of the mitochondrial genome by CE. The low throughput of CE sequencing makes it difficult to incorporate complex DNA testing into routine procedure for criminal labs. Next-generation DNA sequencing technologies have advanced dramatically in recent years, although the high costs to set up and operate these technologies have slowed adoption by criminal labs. With the recent launch of the Ion Torrent PGMtrade;, applications of more complicated contents can be designed for the forensic community to take advantage of the low cost and high throughput features that the PGMtrade; provides.
The whole 16 kb mitochondrial genome can be sequenced on one chip on PGMtrade;. If sequenced on CE, 64 separate reactions would be necessary (assuming 500 bp amplicons and forward/reverse sequences). We can simultaneously sequence whole mitochondrial genomes from 25-50 individuals on one 316 chip. It is also possible to combine many currently used STR kits such as Identifiler, YFiler, NGM Select, as well as phenotypic SNPs, autosomal SNPs, Y SNPs, and Indel markers into one testing kit.
To test the feasibility of this idea, we have built an assay system in which we designed 32 PGMtrade; A-fusion adaptors with a short sequence tag made of different combinations of nucleotides attached to the A adaptor (barcode). We have amplified the whole mitochondrial genome with 2 PCRs each yielding overlapping 8-9kb amplicons. The two PCR products were then combined, sheared, and ligated to P1 and A-fusion barcoded adaptors. The PCR products from each individual can then be pooled and sequenced on the PGM on one chip. Additionally, for more compromised samples, we have created a 2 PCR mitochondrial mini amplicon system consisting of 2 multiplexes of 5 primer sets spanning the mitochondrial control region.
To demonstrate feasibilty of the SNP assay, we have constructed a panel of 103 autosomal and 35 Y chromosome SNPs selected from publically available datasets. A single PCR multiplex for ~200 bp amplicons covering the 138 SNP loci has been generated using the AmpliSeqtrade; Designer pipeline. The PCR products were ligated to P1 and A-fusion barcoded adaptors. Barcoded libraries from 32 individuals were pooled and sequenced on one chip on the PGMtrade; and compared to reference genotypes.
DNA PROFILING OF DATABASE REFERENCE SAMPLES USING SECOND GENERATION SEQUENCING
Carey Davis, David H. Warshauer, and Bruce Budowle; Institute of Applied Genetics, Department of Forensic and Investigative Genetics, University of North Texas Health Science Center
Fourteen years ago, a core set of forensic markers was selected for the United States national databank, COmbined DNA Index System (CODIS). This databank houses over 10,400,000 DNA reference profiles comprised of autosomal STRs from convicted felons and arrestees. These profiles have been used to develop many investigative leads for a variety of crimes. The database size continues to grow and additional search strategies have been considered. The expanded applications that CODIS has experienced over its 14 years warranted a reconsideration of whether the current core loci are sufficient. There is general agreement that the core STR markers for CODIS needs to be increased; but there are differences of opinion on what criteria and how best to proceed with core marker selection. While choosing a core set of markers is useful for formalizing a common set for data exchange, this concrete set inadvertently can limit progress and stifle innovation for alternate markers that may serve well the specialized forensic community needs. However, these discussions on a fixed core set of loci and unintentional stymied growth of novel marker sets can be rendered moot with the advent of second generation sequencing (SGS). With this technology, it is possible to analyze a large battery of forensically relevant genetic markers simultaneously with economies of scale once not thought possible. Furthermore, the high throughput capacity of NGS technology makes possible multiplexing of 12 to 384 individuals in a single reaction. Additional barcodes can increase sample throughput an order of magnitude. Instead of focusing only on a core set, a comprehensive (although small by SGS capabilities) panel of 31 autosomal STRs, 26 X STRs, 29 Y STRs, and 378 forensically relevant SNPs (both identity and bioancestry) was created using two separate sample preparation methods: TruSeq by Illumina and HaloPlex by Agilent Technologies. Analysis was carried out on an Illumina GAIIx instrument which has a throughput in 50-100 gigabase range and far surpasses coverage requirements.
Key Results: All 378 identity and ancestry SNPs called. 17 of 18 Y STRs called, and 17 complete and 3 partial of 21 autosomal STRs called.
Samantha Peek, John D. Jermain, Brittany M. Crane, Bureau of Alcohol, Tobacco and Firearms
Firearm enthusiasts train with exploding targets to improve their accuracy and for recreational purposes. When a bullet makes contact with a target, the container will explode on impact. An exploding target is a type of binary explosive consisting of an oxidizer (i.e. ammonium nitrate) and a fuel (i.e. aluminum powder). As part of our research, we are analyzing various mixtures of exploding targets utilizing Scanning Electron Microscope/ Energy Dispersive Spectroscopy and X-ray Diffraction to ascertain what material is present in the binary explosive mixture.
Exploding targets currently do not have any regulation within the government and there are no laws indicating it is illegal to make the binary explosive, as long as the targets are not transported. It is important we research the targets because these are binary explosives that are highly unstable and dangerous if able to detonate on impact from a bullet.
FIBER EVIDENCE: A CASE STUDY
Peter Barnett; Forensic Analytical Sciences, Inc.
Skip Palenik; Microtrace
Fibers that are transferred from one object to another can be evidence of contact between the two objects. Fibers from two different objects in the home of an apparent abduction and murder victim were recovered from a suspect's vehicle. A total of approximately 17 different fibers recovered from tape lifts from the suspect's vehicle were found to be indistinguishable from fibers from two objects in the victim's residence. A variety of analytical tests were performed on these fibers and the results of those tests will be presented. The analytical tests provide strong evidence that the fibers could be from the two items from the victim's residence, or any similar items. Are we answering the right question? How do we address other questions in this case? The question relevant question is, "Are these fibers from the recovered objects?" Does the forensic scientist have any obligation to address this question? Assuming that the question can be addressed, the next question is "How did the fibers come to be present in the suspect's vehicle?" Does the forensic scientist have an obligation to answer that question? One of the authors (Palenik) will present the analytical results leading to the conclusion that fibers from the vehicle could have come from the recovered objects. The other author (Barnett) will address the question of how that evidence can be evaluated, and address the obligation of the forensic scientist to attempt to answer the question of the significance of the evidence.
THE FALLACY OF ACCREDITATION
Dr. Robert Shaler, PSU Retired
NO ABSTRACT SUBMITTED
NIST BULLET SRM 2460 REPLICATION AND VALIDATION USING AN IMPROVED VACUUM CASTING METHOD AND POTENTIAL EVIDENTIARY USE
R.M. Thompson, A. Zheng, B. Renegar, J. Song, J. Yen, and T. Vorburger; Law Enforcement Standards Office & Surface and Nanostructure Metrology - NIST
In 2011 the Law Enforcement Standards Office (OLES) at NIST entered into technology transfer agreement with the German Bundeskriminalamt (BKA) whereby NIST could use their current polymer replication method to produce the next generation of NIST Bullets (SRM 2460). Within a few months the NIST Project Team had adapted the process using polymer materials more easily obtained in the United States. The replica bullet surface profiles were measured using the same exacting methods used to qualify the Bullet SRMs. Results of those comparisons reveal that the cast replicas are virtually identical to the original SRM bullet that was cast. Another casting procedure is being developed for cartridge cases, bullets, and toolmarks that will be more "crime lab friendly" in materials and hardware. In this way crime laboratories may have the option to make replicas of evidence using a tested and accurate process. These replicas could be shipped to another agency for analysis without the risk of losing the original evidence. Additionally, proficiency/training sets can be produced that are identical in quality to the original items. The European Network of Forensic Science Institutes Expert Working Group on Firearms and GSR (ENFSI EWG FA/GSR) has sponsored proficiency tests using the vacuum casting method with great success.
PROPOSED "NIST BALLISTICS IDENTIFICATION SYSTEM (NBIS)" BASED ON 3D TOPOGRAPHY MEASUREMENTS ON CORRELATION CELLS
Jen-Feng Song, Wei Chu, Robert M. Thompson, Law Enforcement Standards Office - NIST
The proposed "NIST Ballistics Identification System (NBIS)" using 3D topography measurements on correlation cells can facilitate high accuracy and fast ballistics identification and evidence searches. The correlation cells can identify "valid correlation areas" and eliminate "invalid correlation areas" from identification. The proposed "synchronous processing" can significantly increase correlation speed. Based on the concept of correlation cells, a Congruent Matching Cells (CMC) method using three identification parameters is proposed for ballistics and toolmark identifications and for high accuracy and fast ballistics evidence searches. The proposed method can be used for correlations of both geometrical topographies and optical intensity images. All the parameters and algorithms are in the public domain and subject to open tests. An error rate reporting procedure can be developed that can greatly add to the scientific support for the firearm and toolmark identification specialty, and give confidence to the trier of fact in court proceedings.
BRIDGING THE GENERATIONS - PANEL DISCUSSION
Ray Davis (Moderator), Keith Inman, Wayne Moorehead, John Houde, Greg Matheson, Dr. Norah Rudin
The field of criminalistics is a-changin'. All areas of human endeavor change, but science and technology is particularly prone to rapid evolution. My first major in college was medical technology until I saw first-hand how mundane that job could be. I pursued a career in criminalistics because I felt it was one of the few remaining jobs that allowed freedom of creativity and independence of thought. When it's just yourself at the crime scene or on the witness stand, you must rely on your wits, experience and high ethical standards. Today I wonder how many criminalists even expect to go to a crime scene or testify in court. Some specialty areas of the lab don't allow bench-level personnel to interpret the results of their own analysis. I fear "medical technology" has come to the crime lab.
The experiences of the next generation of criminalists will be as different from mine as mine were from my father's generation. I heard him tell crime lab stories (he was police photographer) and felt envious of those "wild west" days of early forensic science. Everything they did was groundbreaking. My generation saw the introduction of certification, accreditation, government oversight, proficiency testing, and DNA testing. The next generation won't recall the days before O.J. and CSI swung the public spotlight onto the profession. It's always hard to endure the loss of freedom, but the next generation will take it in stride. Will their career be as much fun?
As we sit at the bench hacking the next swab, scraping the next pill, or taping the next garment, we probably do not think of our work as requiring any courage on our part. We have the protocol in front of us, a shelf full of binders proving the mettle of our work through accreditation and validation, and a supervisor who reviews all of our work, ensuring that we have evaded the land mines. We have what we need.
Conversely, think for a moment about the origins of the CAC; now that was a courageous bunch. This organization was started by 13 men who felt that their expertise, skill, knowledge, and general ability to fulfill their function was impaired if they could not interact with one another. At the first meetings (where they frequently hosted each other at their PERSONAL HOMES) they could discuss their successes, their failures, and how the field could advance. They were never funded by their agency. Ever. Now that took courage, and we no longer feel the need for such pluck, do we?
It is certainly seductive to believe that we are surrounded by a safety net; the protocol, the certificates and diplomas on the wall, the terabytes of data and literature supporting our conclusions, all point to our feet situated on solid ground. Until our supervisor tells us to analyze this piece of evidence, because the captain says so. Or our sample becomes contaminated when someone forgets, or neglects, to clean the space or implements properly. Or when it is lab policy to never talk to the detective about the needs of the case. Or when an attorney suggests that we use *this* word instead of *that* one because it sounds better to the jury, and is more in line with legal jargon. Or when a detective, at an officer involved shooting, forbids you to collect a specific, relevant piece of firearms evidence. Or when we discover, on the witness stand while giving testimony, that we have misplaced a decimal point in our quantitation. And then, suddenly, we need to start channeling Braveheart. One of my hard-won aphorisms goes something like this:
"We don't matter; only the evidence matters. Our embarrassment, censure, counseling, and reprimands don't matter. Only the accurate portrayal of the physical evidence and its meaning matters."
And it takes massive and daily courage to make that our priority over everything else.
Dichotomies and Stereotypes: When a group with similar social and professional attributes gathers, the discussion inevitably devolves (or perhaps degenerates) into dichotomies and stereotypes: us vs. them, our values and qualities vs. their values and qualities. On a recent occasion, a group of forensic scientist of a certain age and professional sensibility illustrated this precept. We began with a discussion of our generation vs. their generation and continued to delineate attributes that we felt defined us vs. them. This categorization, the very essence of stereotyping, began to lead us down a dark and convoluted rabbit hole.
While differences certainly exist between any two groups that one might choose to define, it is also true that those differences exist along a continuum, including outliers at both ends of the normal curve. The challenge, as I currently see it is, how do we facilitate intentional and voluntary communication between, not only the generations, but between public and private labs, and between government and independent analysts. The gulfs are as wide and sometimes appear as impassable. I propose these ideas as part of our ongoing discussion.
There were two important times in my life where the experience of others helped to shape my professional life. The first was in the military and the second, at beginning of my forensic career. I was an infantry officer during the Viet Nam war working closely with senior non-commissioned officers. No matter how well I had been trained, I was worried about doing my best. Whenever I encountered a difficult problem or received a command I felt challenged to complete, I sought the counsel of these old warriors. I was surprised and delighted by their attitude making my time in the service an incredible experience. I have never forgotten how important it is to ask for help and I encourage you to do the same when faced with a new challenge.
I began my career with DOJ forty years ago in a refurbished cannery located at 3301 C Street in Sacramento. I didn't even know the word criminalistics until a few months before starting my career. Because of limited laboratory space, we had to double up by starting our training classes at noon and finishing at eight during the three week blood alcohol course. One of the clearest memories I have of those times was the generosity of the technical staff as they guided us through our training. They answered our questions and encouraged us along the way. Our instructors were just as committed to our success making our training a memorable experience. Reflecting back, I am grateful for the wisdom and advice of the people who have contributed to my success.
Fact is Fact but Perception is Reality; this is something I heard Dr. George Sensabaugh say at a CAC meeting many years ago and it has stuck with me ever since. Are the perceptions of the "seasoned" criminalists correct in thinking that new criminalists are not interested in learning from the old? Do the new "New Silent/Generation Z" or "Y-Generation" criminalists think they know it already or that their immediate peers know better than those with years of experience? Is it simply a matter that the new and the older experienced criminalists don't know how to communicate effectively with each other? We've identified this as a new problem but perhaps this is a reoccurring thought by the next generation to fill each of these roles and maybe Tony Longhetti thought the same about me when I entered the field.
The subject of passing along gained knowledge i.e., our experiences, mutated into talk about mentoring while a group of "seasoned" criminalists had dinner one evening last spring. Some of the frustration spoken about had to do with a perceived reluctance by the new criminalists to learn from the experiences of the older criminalists. Does the new generation view the experienced criminalists any different than Wikipedia when it comes to a source of information? We certainly hope not but the internet is so easy to access. We certainly think that our knowledge, gained through study and experience, is much more valuable and in depth than the Wikipedia version and certainly worthy of passing along to the next generation of forensic scientists. Plus the biggest learning experiences I've had has been through one on one or group discussions about different issues. Hopefully these discussions have taught me how to think about the issues, not just gather facts.
Why should new criminalists learn things the hard way when there is a ready living source of information available? If new criminalists learn the hard earned lessons directly from the experienced analysts then they will have time to explore new areas and be able to pass along their new information and knowledge to other criminalists, new and old. I learned early on through interns and trainees that I've had that I can learn something from everyone I run in to. Sometimes those lessons are small, sometimes large but it all adds up to a wealth of experience and knowledge. It also adds up to the fact that the more I learn, the more I realize I don't know.
Compared to the others in this group my career took a somewhat different path. I worked the bench for 11 years in the areas of Toxicology, Crime Scene Analysis, Poisons and explosives analysis and mostly Serology. In my 12th year I was promoted to a supervisor (in a laboratory which was large enough that supervisors rarely performed casework), then an assistant laboratory directory and eventually laboratory director. My perspective of the evolution of generations in the crime laboratory is by necessity somewhat different.
There have been many changes in the world since I started as a criminalist in 1978. All of those changes have the potential to affect how people do their jobs, how they view professionalism and whether they choose to make their money earning activities a job or a profession. It's important for those of us who have been in the profession for several decades to give some thought and consider how we might be serving our profession if we entered the field today and then use that enlightenment to make us better mentors and leaders.
As an example, if you consider only the changes in the laws that govern work we can see how today is a very different world for employees and employers and could affect how the current generation of criminalists view and approach their work. Not many years ago, to be considered a dedicated professional you stayed after work as needed, on your own time, to finish an experiment or you took literature home with you to ensure you completed study required by your laboratory to learn a new technique or procedure. However, starting about seven years ago, as a Laboratory Director I was required by the federal Fair Labor Standards Act and the policies of the Los Angeles police Department to discipline any employee who continued to work past their end of watch without prior approval, even if it was as little as six minutes extra to finish writing up their notes, wrap up an experiment, or clean their bench. Though this sounds absurd and seems like it can only result in crushing people's desire to go the extra mile and do what is necessary to get the job done right (be a dedicated professional), it became a necessity due to changes in the work place. It is our job as supervisors and managers to help people accomplish what needs to happen while maintaining interest and professionalism and meeting legal requirements.
We need to learn how to adapt to the changing conditions of work and life while using our experience, commitment, and knowledge to help the profession and new generations of criminalists move forward and improve without bemoaning what we perceive as negative change.
I have been known at times to ask questions; sometimes, too many questions. So rather than tell you what I think, I'm going to ask questions that I believe you should begin to explore.
- Why are you in this profession? And, is this a job or a profession to you?
- Do you consider yourself a technician or a scientist?
- Do you perform only what is asked or do you explore, question, and provide more service than asked?
- Are you reading scientific literature, forensic or otherwise, when you are not being paid to do so?
- If you see potentially relevant evidence, do you alert the investigator, attorney, or perhaps another scientist to its presence?
- When appropriate, do you explore hypotheses other than the one proposed by the investigator or attorney?
- Are you sharing your casework and courtroom knowledge/experience with others?
- Would you attend a meeting on your own time using your own resources?
- Assuming there was no explicit support by management; would you do research and give a technical presentation on that research at a meeting?
- Do you find seeking advice from peers to be a sign of weakness?
- What is the most difficult aspect of your work? How could you make it less difficult?
- Is there a better way to do the analysis without compromising quality or forensic integrity?
- How would you improve the CAC, these seminars, or the profession?
- Do you know and understand the purpose of ISO 17025 and ASCLD-LAB accreditation requirements?
- After today, how will you change or what will you change to become a more valued member of the forensic community?
- How can we help you to achieve the potential we see in you?
USE OF QUANTIFILER DUO TO SCREEN SEXUAL ASSAULT EVIDENCE
Adam Dutra, San Diego PD Crime Laboratory
Traditionally, the San Diego Police Department has used microscopic examination for the detection of sperm cells as a method to screen sexual assault examination evidence for suitability for DNA testing. Although the quantity of sperm cells can be used as a rough estimate of the amount of male DNA in a sample, male DNA can come from body fluids other than semen. Additionally, microscopic examinations are time intensive and attempts to automate the process are costly and have had mixed success. SDPD uses Quantifiler Duo to quantitate both human and male DNA simultaneously and has recently employed this DNA quantitation method to screen sexual assault evidence in lieu of microscopic screening. This presentation will provide some of our motivations for this change, brief descriptions of our prior and current procedures, highlights of our validation, and a few notable successes to date.
ARMEDXPERT™: A SOFTWARE TOOL FOR MIXTURE DECONVOLUTION AND CASE MANAGEMENT OF STR RESULTS
Rhonda K. Roby, PhD, MPH; University of North Texas Health Science Center, Department of Forensic & Investigative Genetics, Institute of Applied Genetics
Dennis J. Reeder, PhD; Reeder Analytical Consulting, LLC
ArmedXpert™ (NicheVision Forensics, LLC, Akron, OH) is a mixture deconvolution software program that also contains many features for casework management. ArmedXpert is designed to automate the tedious and numerous calculations required to thoroughly review a mixed STR DNA result. This software not only aids the forensic DNA analyst in these routine, time-consuming computations but it also provides an array of significant other functions. ArmedXpert has a user-friendly interface to import tabular data, to compare sample results, to identify matches within a case file and in multiple databases, and to conduct critical quality control evaluations. The quality control interface allows the user to check ladders, check controls, and detect possible stutter. The software performs matching between evidence samples and references and evaluates possible contamination by staff. The software is designed to perform CODIS functions; conduct mixture interpretation with two to three contributor mixtures; view simulated electropherograms; chart data; perform various biostatistical analyses for single and multiple source samples; and print and save data.
ArmedXpert is a software program that can be easily adapted and implemented into the forensic analyst's toolbox. This program has many features that will assist forensic analysts to fully evaluate and summarize their data. ArmedXpert can be used as a stand-alone program or can support DNA analysts in their arduous task of mixture interpretation and used in conjunction with other software programs.
In this presentation, various examples will be shown to demonstrate the ease and power of the software. The attendee will gain an understanding of the need for a deconvolution software tool and the advantage of having many tedious calculations being made nearly instantaneously.
THE POWERPLEX® Y23 SYSTEM: A SINGLE SYSTEM FOR CASEWORK AND DATABASE (DIRECT AMPLIFICATION) Y-STR ANALYSIS
Sara Laber, Jonelle M. Thompson, Margaret M. Ewing, Patricia M. Fulmer, Dawn R. Rabbach, Cynthia J. Sprecher, and Douglas R. Storts. Promega
Y-STR testing is an established tool in the forensic casework, paternity testing and genealogy communities. The PowerPlex® Y23 System combines the seventeen Y-STR loci in current commercially available Y- STR kits (DYS19, DYS385a/b, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, Y- GATA-H4) with six new highly discriminating Y-STR loci (DYS481, DYS533, DYS549, DYS570, DYS576, DYS643). The additional loci and increased gene diversity increases scientists' ability to distinguish individuals from different paternal lines from one another, enabling more meaningful analyses. The PowerPlex® Y23 system is a robust multiplex highly tolerant of many amplification inhibitors, including hematin, humic acid, and tannic acid. The system has proven sensitivity, detecting minimal amounts of male DNA in the presence of excessive amounts of female DNA. Complete Y-STR profiles are detected with 62pg of male DNA in the presence of 400ng female DNA (6450-fold excess). This Y-STR system is an excellent tool for testing in sexual assault cases in which sperm was not detected from intimate swabs collected from female victims. The PowerPlex® Y23 system also supports direct amplification from a variety of substrates, including blood and buccal samples on FTA® paper (GE Healthcare/Whatman) and other commonly used paper substrates. This system produces reliable Y-STR profiles from swabs when processed with Promega's SwabSolution™ Kit. Additionally, Y-STR amplification with this system provides significant time savings due to a reduced cycling time of 90 minutes--less than half the time required for other available Y-STR kits. By offering superior inhibitor tolerance, proven sensitivity, and protocols for both casework and databasing, the PowerPlex® Y23 System sets a new standard for Y-STR analysis.
COMPARING WEARER DNA SAMPLE COLLECTION METHODS FOR THE RECOVERY OF SINGLE SOURCE PROFILES
Corissa J. Harris, Amanda J. Cardenas, Steven B. Lee, Brooke Barloewen; Santa Clara County Crime Laboratory, San Jose State University
Wearer DNA is the deposit of epithelial cells on clothing worn by an individual. Detection of the last individual to handle or wear an item is often an important determination in forensic science. The most commonly used collection methods for wearer DNA include swabbing and scraping. These often result in mixture profiles. The detection of a single individual who last wore or came in contact with an item is desirable. Recently, adhesives have been introduced as a possible reliable method for the collection of biological evidence. Adhesives have a tendency to recover less, but more recently deposited particulate than the current methods because they are less invasive. The ability to observe the collected cells with the aid of a microscope is another advantage of using adhesives.
The goal of the research was to compare the current collection methods of swabbing and scraping with a gel film called Gel-Pak '0' which shares similar properties with adhesives. Gel-Pak '0' has been previously studied in comparison to other adhesives for the collection of epithelial cells, and was shown to recover the top layer of loose particulate. This particulate was deposited by the individual who last came in contact with an item. Therefore, in comparison to the other two collection methods, Gel-Pak '0' was hypothesized to recover single source profiles on clothing items from the most recent wearer. DNA analysis was performed on samples collected by the three methods from various clothing items including baseball hats, t-shirts, sweatpants, socks, and other items commonly submitted to crime labs for DNA analysis. The habitual wearer and second/last wearer wore each item for a predetermined time.
The results of the research showed that Gel-Pak '0' recovered a similar number of CODIS (local and national) eligible profiles as swabbing. However, coupled with the fact that it is time consuming, costly, and cannot be used on all surfaces, Gel-Pak '0' was determined to not make for an effective collection method of the most recent wearer's DNA. Therefore, Gel-Pak '0' will not be considered for casework. Although Gel-Pak '0' will not be further used, the results did reveal some trends that may shed light on how DNA analysts may approach wearer DNA cases. Swabbing had a tendency to yield smaller amounts of DNA but obtain DNA from the last wearer of the piece of clothing more effectively than the other two methods. Scraping had a tendency to yield a greater quantity of DNA but obtain mixtures, including more DNA from the habitual wearer due to its invasive nature. Revealing individuals who last wore an item can be of great importance in forensic science, and therefore, further research with various adhesives and gel films could be vital for solving forensic investigations.
Note: This work was supported by a CAC A. Reed and V. McGlaughlin Scholarship to C. Harris
OVERCOMING INHIBITION WITH PCR ENHANCERS
Phil Nhan, Hanna Bennett, Hillary Nguyen and Steven B. Lee, San Jose State University
Since its introduction in the mid-1980s, the use of DNA, namely DNA profiling, in forensic science has revolutionized the justice system on a worldwide scale. DNA profiling is comprised of multiple steps and procedures including DNA extraction, quantification and amplification using Polymerase Chain Reaction (PCR). PCR has permitted the analysis of very low quantity, low quality DNA samples. However, crime scene samples are often found in very poor condition and are often mixed with extraneous materials that may co-extract with the DNA.
There are several known, commonly encountered inhibitors to PCR: calcium, collagen, humic acid, hematin, melanin, indigo dye, detergents and phenol-chloroform used in DNA extractions (1-6). These inhibitors may interfere with the cell lysis or capture of components necessary for DNA extraction by causing DNA degradation and/or inhibiting DNA polymerase amplification of target DNA (7). A 2012 review on forensic implications of PCR inhibition was published (8).
Although the causes of PCR inhibition are still not fully known, three mechanisms have been proposed 1, 2, 7. These include: 1) binding of inhibitor to Taq polymerase; 2) blocking of amplification sites due to inhibitor-template binding; and 3) decreasing processivity due to interaction of the inhibitor with Mg2+ cofactors or other components of PCR (7).
Detection and overcoming PCR inhibition are critical challenges faced by forensic molecular biologists and many others such as microbiologists studying soil samples, molecular evolutionary biologists studying ancient remains and preserved samples, molecular ecologists studying animal excrements, molecular pathologists studying preserved and mounted specimen, and molecular archaeologists and anthropologists studying ancient human remains.
Commonly utilized methods for overcoming inhibition in the forensic DNA community include:
- diluting the samples (thereby also diluting inhibitors in the sample);
- additional cleaning of the sample by purification;
- including additional DNA polymerase and Bovine Serum Albumin;
- utilizing STR multiplexes that are inhibitor resistant such as MiniFiler, Identifiler Plus and Powerplex 16HS; and
- adding PCR enhancers (9-18).
In this study, a mutant Taq polymerase and two different PCR enhancers were tested for their ability to overcome inhibition: Omnitaq (DNA polymerase technologies, St. Louis, Missouri), PCR enhancer cocktail (DNA polymerase technologies, St. Louis, Missouri references 19 and 20) and PCRboost (Biomatrica , San Diego, CA reference 21-23). Omni taq is an inhibitor-resistant Taq polymerase mutant and PCR enhancer cocktail (PEC) consists of a mixture of nonionic detergent, L-caritine, D-(+) trehalose, and heparin (19-20). PCR and STR boost are proprietary enhancers from Biomatrica Inc (21). Previous tests conducted in our laboratory have shown improved amplification using PCRboost from DNA samples containing indigo dye, hematin, humic acid, and phenol chloroform (21-23).
This project will explore the amplification enhancement of OmniTaq, PEC and PCR boost on low quantity and low quality DNA samples that contain varying amounts of inhibitors. Enhancement will be evaluated on replicate 1, 0.5 and 0.25ng samples with and without inhibitors at different concentrations using qPCR and STR multiplex typing.
Note: This work was supported by a CAC A. Reed and V. McGlaughlin Scholarship to P. Nahn
FORENSIC FACE MATCHING: THE PITFALLS AND PROMISE OF COMPARING SUSPECT AND SURVEILLANCE IMAGES WHEN CRIMES ARE RECORDED ON CAMERA
David DeGusta; Better Forensics
The proliferation of surveillance devices has led to an increasing number of criminals being recorded on camera in the course of committing a crime. When a suspect is apprehended in such cases, a key question is whether the suspect is the same person pictured in the surveillance imagery. This presentation will review methods for testing the hypothesis that an arrested suspect is the same person recorded committing a crime. Qualitative, quantitative, superimposition, and automated approaches will be evaluated. Facial, ear, and postcranial metrics will be included, along with a consideration of the most appropriate statistical tests. Some significant pitfalls in published methods will be described, and a rarely used source of data identified. The goal is to develop a robust protocol for handling forensic photo comparisons that can assist practicing criminalists and serve as the basis for further research.