Thesis (M.S.F.S.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This thesis looks at and analyzes the current body of research into the early-stage formation of adipocere as it pertains to post-mortem interval determination. Adipocere is a waxlike substance that can encase bodies after death if certain conditions are met: temperature, moisture content, other environmental factors, and the presence of bacteria that transform fatty acids into the hydroxy- and oxy-fatty acids that make up much of the adipocere substance. Adipocere formation arrests the process of decomposition, making it difficult for forensic pathologists to determine a post-mortem interval. The thesis identifies several issues with current research into early-stage adipocere. Firstly, the majority of scientific papers on the subject make use of pig adipose as a stand-in for human adipose due to ethical concerns. However, this traditional forensic method is not suited for studies into adipocere formation: the fatty acid profiles of pigs and humans have differing ratios of saturated and unsaturated fatty acids, making them an unreliable analog for adipocere testing. In addition, most studies assume a three-month timeframe for the formation process when preparing their experimental design, a timeframe thrown into question by both current data and several existing case studies demonstrating more rapid adipocere formation. Lastly, testing takes place in static environments, which does not reflect actual field conditions. There have been cases that suggest adipocere formation ceases during colder months once decomposition has initially halted. In these cases, the adipocere formation begins again once temperatures return to 22°C or higher. Another issue noted is the lack of chemical analysis conducted on early-formation adipocere. The changes in fatty acid ratios that take place during the process are not typically looked at by scientists investigating the phenomenon or forensic pathologists dealing with adipocere cases, but may offer a viable means of narrowing down post-mortem intervals and contribute to better timelines for pathologists and law enforcement. This thesis ultimately recommends a number of additional research directions necessary for building a temperature zone-based database of case and laboratory results, particularly ones that take into account the variable formation timeframe observed in previous experiments and case studies. / 2031-01-01

Attitudes towards sexual offenders have been widely studied in forensic psychology and criminology research over the past 25 years. At present, however, studies examining these views are predominantly descriptive in nature. That is, self-report questionnaire measures are typically distributed to different groups (e.g., general public samples, and members of different occupational categories), with the resultant between-groups differences being reported in research papers. While these studies have provided some interesting findings, the results gained from them fail to inform researchers about the psychological mechanisms that underpin views about this offending population. The overarching aim of this thesis was to begin to fill this knowledge gap. That is, a range of studies were designed to use robust experimental methods, within validated theoretical paradigms, in order to examine some of the potential constructs that influence people’s attitudes towards sexual offenders. Chapter 1 presents a review of the current state of the field in relation to attitudes towards sexual offenders, with gaps in current knowledge being identified. In Chapter 2, the theoretical framework within which the empirical aspects of the thesis operate is set out. Key constructs in this section include dual-process cognition, and our reliance on implicit (i.e., non-conscious) mental processes when making decisions. Chapter 3 builds upon criticisms of one measure of attitudes towards sexual offenders in order to reconceptualise its use into one of an outcome measure. This is then used throughout Chapters 4, 5, and 6 as a measure of sentencing and risk judgements, in order to examine the effects of various experimental manipulations. Studies presented in Chapter 4 found that heuristic-based processes based around the principles of availability appear to influence decision-making about sexual offenders at the macro (political) level, but not at the micro (individual) level. Instead, individual participants’ attitudes and judgements about sexual offenders were dependent on different primes relating to the representativeness (Chapter 5) and affect (Chapter 6) heuristics. Chapter 7 offers a discussion of the empirical findings presented at earlier points of the thesis, and outlines opportunities to develop further work into the heuristic-based nature of attitudes towards sexual offenders. The work contained within this thesis is original, in that well-validated theoretical models are used to begin to examine the psychological mechanisms that may underpin attitudes iii towards sexual offenders. The apparent dual-process nature of such views calls into question some previously-expressed calls within the literature that presenting fact-based information about sexual offenders may lead to improvements in societal attitudes. Instead, it may be that more indirect and emotional methods may be required to achieve such aims. Towards the end of the thesis, clear opportunities for further work are set out, as are some of the potential implications of this research.

Research on crime scene investigation has strongly focused on the technical aspects of the process, while cognitive aspects (searching, reasoning and perception) have often been overlooked. Textbooks on forensic sciences tend to focus on identifying and processing evidence, and the use of equipment while it can be argued that cognitive factors in processing such evidence and using equipment are equally important. This thesis studies the cognitive aspects of crime scene investigation by comparing eye movement patterns in experts and novices. Studies in various domains, including surgery, sports, and chess playing have shown that eye movements differ between experts and novices, providing a tool towards a more objective assessment of skill than is possible with peer assessment. In four experiments eye movements of experts and novices were examined during (1) inspection of photographs of crime scenes on a computer screen (2) a change blindness task on crime and non-crime scene images, (3) active exploration of a simulated crime scene and (4) the assessment of emotional crime and natural scenes. While some trends in eye movement differences, such as a tendency on longer fixation durations and a broader focus on the overall scene and less on the direct evidence could be found in experts compared to novices, differences between experts and novices were considerably smaller than in other domains, despite the broad range of measures extracted from the data. This lack of clear expertise effects may relate to the rather diverse range of perceptual layouts of crime scenes, reducing possible top-down effects of expertise on the deployment of attention. The results will be discussed with a view of possible directions of future research in this domain.

Fingernail evidence is often collected in criminal cases of violent and/or sexual assault. In acts of aggression and self-defense, foreign deoxyribonucleic acid (DNA) can be transferred from the perpetrator to beneath the surface of the fingernail of the victim. It is possible to recover this foreign, exogenous DNA from the victim’s fingernails and potentially identify the perpetrator via DNA analysis. When attempting to recover this DNA from fingernail clippings, a couple of problems can occur. Often times, not enough exogenous DNA gets trapped underneath fingernails, so there is not usually much DNA to work with for recovery. The other major problem is the presence of endogenous DNA from the fingernail donor. Not only is there donor DNA in the fingernail itself, but the donor’s own DNA can build up underneath their nails simply by rubbing their face or combing their fingers through their hair. This means that there can be more donor DNA present that can mask the presence of the foreign DNA and cloud the results. In an attempt to improve the recovery of foreign DNA and produce a reportable, informative profile, a time course study was developed. Typically, when using forensicGEM as an extraction method, the samples would incubate for 15 minutes before going through protease inactivation. For this study, the extraction period was broken up into four 5-minute periods of incubating, for a total of 20 minutes, before inactivating the protease. This was done to pinpoint the time period at which more foreign DNA is being extracted from the surface of the nail before endogenous DNA is extracted in excess and clouds or even hides the presence of foreign DNA altogether. Female fingernail clippings were spiked with neat male saliva to observe the ratio of male to female DNA during quantitation and on the electropherograms. The quantitation results depicted a strong presence of male DNA through the entirety of the time course, and female DNA did not appear to be extracted in greater levels until the 15 minutes of incubation. The resulting profiles exhibited the male saliva profile as the major contributor for most of the samples, especially at the 5- and 10-minute markers. In 50% of the profiles, a minor female contributor could be identified as the nail donor. One sample produced a single, male profile for each time point with no indication of a female donor present in the extract; another sample produced a profile with a male major contributor with only 3 to 6 loci having additional detectable alleles of a minor contributor at each time point. These alleles could not be conclusively attributed to the female nail donor, but she could not be excluded. These preliminary results indicate that a shortening of the forensicGEM extraction period could be beneficial for improving the recovery ratio of exogenous to endogenous DNA from fingernail evidence.

Processing sexual assault samples is a difficult time consuming task for the forensic analyst. Samples tend to be a mixture of the victim’s epithelial cells and the male suspect’s sperm cells that need to be separated prior to extraction of Deoxyribonucleic Acid (DNA). Without separation of the two cell types, the DNA extract would result in an uninterpretable mixture. In 1985, Peter Gill and colleagues outlined a procedure known as preferential lysis that would aid in the separation of female and male cells from sexual assault samples. The basis of this procedure, commonly referred to as a differential extraction, utilizes differences in the packaging of DNA between the two cell types to preferentially lyse the female epithelial cells and leave the sperm intact. By pelleting the sperm and removing the supernatant (termed the Non-Sperm Fraction) the Sperm Fraction can now be extracted without the contaminating epithelial cells. This procedure has been widely implemented in forensic laboratories and is still being used today over 30 years later. However, there are certain conditions under which this procedure does not perform sufficiently including excess of female epithelial cells and low amounts of sperm. Unfortunately, both of these conditions are common among sexual assault samples. The procedure also is quite long, and with the backlog of sexual assault samples continually growing in the United States, there is a need for a new procedure that is faster and performs optimally under the previously mentioned conditions. This research explores the use of two enzymes, EA1 (marketed by Zygem Corporation as ForensicGEM Saliva™) and Trypsin to separate the cells. Due to the inability of Zygem to cleave the disulfide bonds present in the sperm DNA packaging proteins, treatment of mixed samples with Zygem will lyse the epithelial cells and leave the sperm intact. The incubation time of Zygem is much faster than that of the Gill method and can be performed in one tube, minimizing the chances of DNA loss and contamination during transfers. Treatment of the pelleted Zygem extract with Trypsin effectively and rapidly lyses the sperm cells. Combining these methods into a differential extraction protocol has the potential to be a rapid, easily implemented procedure. Results from the Zygem-Trypsin differential extraction method showed incomplete separation of the two fractions due to the incomplete lysis of the epithelial cells by Zygem. The resultant profiles did show a major male contribution with a minor female component, however these results are not sufficient enough for real casework. While further research and development of the protocol are necessary, the Zygem-Trypsin differential extractions performed here show the potential for a rapid, easy differential extraction procedure that could be easily implemented in any laboratory. / 2017-11-03T00:00:00Z

The Peganum harmala plant is a flowering shrub that produces small, dark brown seeds in pods. These seeds contain the hallucinogenic alkaloids harmine and harmaline. As such, they have been historically used for shamanic rites and folk medicine. Presently, P. harmala seeds are commercially available and subject to no legal restrictions in the United States. This has allowed for the recreational use and abuse of these hallucinogenic seeds or seed extracts made with household chemicals. Overdose cases from excessive consumption of seeds or seed extracts have been reported. Overdose patients present with hallucinations, tremors, agitation, tachycardia, and gastric distress. Severe overdose cases have resulted in hospitalization for respiratory depression and coma. The goal of this research was to develop a protocol for forensic analysis of suspected P. harmala seeds. Physical examination was selected as a quick, cost-effective preliminary method to screen seeds. P. harmala seeds are, on average, approximately 2.3 ± 0.3 mm long and 1.0 ± 0.2 mm thick, with an average Feret’s diameter of 2.8 ± 0.3 mm. The mean mass of one seed is 2.5 ± 0.2 mg. The seeds are dark brown, irregularly shaped, and have a pitted surface. Seeds matching these descriptors can be further analyzed to detect harmine and harmaline. Direct analysis in real time (DART) allows for very rapid mass spectral analysis of P. harmala seeds. Ions corresponding to harmine and harmaline can be detected when an intact seed is placed in front of the DART ion source, and higher levels of harmine and harmaline are observed when a seed cut in half to reveal interior surfaces is analyzed. Solvent extraction of crushed seeds using ethanol followed by gas chromatography – mass spectrometry allows for confirmation of the presence of harmine and harmaline in suspected seeds. When selected ion monitoring is used, this method is able to detect harmine and harmaline in a sample consisting of a single seed. Infrared spectra of harmine and harmaline standards, crushed P. harmala seeds, and solid material obtained from evaporating off the solvent from an extraction of crushed seeds were obtained. Infrared spectroscopy can be used to distinguish between pure harmine and harmaline, but is a poor choice for analysis of samples containing a mixture of harmine and harmaline, such as P. harmala seeds. In conclusion, physical characterization, direct analysis in real time, solvent extraction, and gas chromatography – mass spectrometry are recommended techniques for the forensic analysis of P. harmala seeds.

The ability to confidently obtain deoxyribonucleic acid (DNA) profiles from a variety of sample types in a crime laboratory is very important. The first step in the analysis of DNA in a forensic crime laboratory is the extraction of the nucleic acid material from the rest of the cellular material contained in the sample. There are many different extraction methods available for use in the field of forensics but one that is reliable, cost effective, and easy to use is necessary. One of the methods that meet these requirements is a solid-phase extraction utilizing a silica membrane that binds the DNA in the presence of chaotropic salts. This solid-phase extraction using a silica membrane is ideal for automation and use with a bio-robot. One commonly used instrument is the BioRobot EZ1® system (Hilden, Germany) from Qiagen®. Automation using these robots was the first step in decreasing the time it takes to perform extraction as well as reduce the potential for contamination, but there are still opportunities to improve in both of these areas. In this study the Qiagen® Lyse&Spin Basket Kit was evaluated due to its potential to further decrease the time needed for extraction and the eliminate a step of the extraction process where contamination could be introduced. Laboratories around the country have reported problems with using Buffer G2 as an extraction buffer when used with samples such as blood on fabric. The reason for this is currently unknown, but in order to continue to confidently extract samples of this type, a change to diluted ATL buffer was suggested. The current extraction buffer, G2, used in the extraction protocol at the Kansas City Police Crime Laboratory was not yielding results in some situations such as blood on fabric. Switching to diluted ATL yielded the same quantity of DNA and the same quality of DNA profiles with mock casework samples. When diluted ATL was used with Quality Control (QC stain) samples it yielded significantly more DNA during extraction. When the Qiagen® Lyse&Spin Basket Kit was used during the extraction of whole blood on fabric (QC stain samples) they showed a significantly lower quantitation value than the tubes currently used in the Kansas City Police Department Crime Laboratory. The same results were obtained when the Qiagen® Lyse&Spin Basket Kit was used to extract 1:2 diluted saliva samples. When samples with lower quantities of DNA, such as 1:100 blood dilutions, 1:50 saliva dilutions, and mock casework samples, were examined the Qiagen® Lyse&Spin Basket Kit there were no significant differences seen when compared to the currently used baskets. When the quantitation data was analyzed for the QC stain samples extracted with the Qiagen® Lyse&Spin Basket Kit, abnormally high degradation index (DI) values were observed. It was determined that these high values did not affect the integrity of the sample. In order to determine the possible cause behind the poor performance of the Qiagen® Lyse&Spin Basket Kit when used to extract samples with higher starting amounts of DNA an experiment was designed to determine if genetic material was left on the cotton swatch in the spin basket. It was seen that DNA was left behind on the cotton swatches from both the Qiagen® Lyse&Spin Baskets and the currently used baskets. It appeared that more DNA was contained on the fabric used with the Qiagen® Lyse&Spin Basket, but further research is needed to determine if this difference is significant.

In 2010, Bright et al. created two person mixtures to determine how effective traditional differential extraction was in determining mixtures by examining mixture proportion variation by using the peak heights from each sample. This project aims to follow that method, however, in this case using a Temperature Controlled Differential Extraction (TCDE) to analyze post coital swabs in place of a traditional differential extraction. The project also aims to determine how efficient the separation of sperm cells from epithelial cells was by comparing the mixture proportion mean of male deoxyribonucleic acid (DNA) from an Acrosolv digest that did not undergo the TCDE to the proportion of male DNA from the TCDE. The amount of DNA remaining on a swab after undergoing the TCDE was also assessed as a material fraction. Many of the material fractions generated a mixture in their profiles and thus enough DNA to generate a male profile was remaining on the swab after the TCDE in almost all cases. The sperm fractions were mostly single source male profiles or profiles with the male DNA as a major contributor and the female DNA as a minor contributor.

Generally, biological samples are collected from crime scenes using swabbing, cutting, or taping techniques. However, these methods are limited in their abilities to recover diluted, masked, or otherwise invisible stains. Additionally, their targeted nature allows only a small portion of a larger stain to be collected at one time. In this study, a sterile wet-vacuum collection system was evaluated in its ability to collect small volume bloodstains from various substrates. Vacuuming was compared to swabbing and taping methods currently used in forensic analysis. Samples were collected from porous and nonporous surfaces; the efficacy of each collection method was evaluated with a colorimetric presumptive blood test. To evaluate each collection method, dilutions containing from 0.25 nl to 25 μl human blood were spotted on common substrate materials, allowed to dry, and recovered. For comparison to the novel method, single-swabbing and tape-lifting techniques were performed in this study to collect samples for presumptive testing. During wet vacuum collection, stains were saturated with sterile buffer and suction was applied to the surrounding area, accumulating buffer in a collection bottle. Collected buffer was then filtered through membranes to capture cellular material, which were then presumptively tested for the presence of blood. Testing was performed with Kastle-Meyer (phenolphthalein) reagents. Each sample was photographed under consistent conditions in order to determine signal intensity. It was shown that the wet-vacuuming technique is able to recover sufficient amounts of blood for presumptive testing from multiple substrates. This method was able to detect similar dilutions of blood as traditional techniques in samples collected from porous surfaces, but was less effective on a nonporous substrate. Presumptive test image analysis shows increased relative intensity in collections from textiles, such as denim, when using the wet-vacuum system. Considering the results of a contemporaneous DNA quantification study, it was shown that in instances where a very weak presumptive result is found, the wet-vacuum technique may be better able to collect genetic material for downstream processing than the traditional methods evaluated. This study demonstrates the potential of wet-vacuuming as a suitable alternative technique to collect adhered cellular material from substrates in forensic investigations.

Postmortem fingerprint collection is a common practice at medical examiners’ offices. Fingerprints are often collected with electronic scanners or ink pads and fingerprint cards. However, obstacles to obtaining clear impressions such as rigor mortis and decomposition can be difficult to overcome using the current methods. There is no clear best method for collecting these compromised fingerprints. The GelSight Mobile™ is a handheld three-dimensional contact imaging system that can measure the topography of any surface regardless of the lighting conditions of the environment. The resolution of the images created is extremely high and can be used to measure single micron features. The goal of this project was to determine if the GelSight Mobile™ was a suitable method for postmortem fingerprint exemplar collection, and to determine if it provides a higher quality fingerprint impression than current postmortem fingerprint collection methods. For this study, three methods – black ink, two-dimensional scanning, and the GelSight Mobile™ – were used on decedents with varying ranges of decomposition to determine the best method for postmortem fingerprint collection. The postmortem interval for the decedents ranged from one day to almost one year, with the latter being exposed to outdoor environments for approximately two weeks prior to discovery and then stored for over a year. Embalmed cadavers were also examined. The results revealed that the GelSight Mobile™ captured fingerprints of higher quality, specifically with higher percentages of prints with level three detail and higher counts of minutiae characteristics than the other methods. However, to be optimized for forensic fingerprint collection, it is recommended that the GelSight Mobile™ be adapted to incorporate a larger gel cartridge and software capabilities to include a mirrored image option and a filter to give images an ink-like appearance.