Speech Watermarking: An Approach for the Forensic Analysis of Digital Telephonic Recordings*

Abstract: In this article, the authors discuss the problem of forensic authentication of digital audio recordings. Although forensic audio has been addressed in several articles, the existing approaches are focused on analog magnetic recordings, which are less prevalent because of the large amount of digital recorders available on the market (optical, solid state, hard disks, etc.). An approach based on digital signal processing that consists of spread spectrum techniques for speech watermarking is presented. This approach presents the advantage that the authentication is based on the signal itself rather than the recording format. Thus, it is valid for usual recording devices in police‐controlled telephone intercepts. In addition, our proposal allows for the introduction of relevant information such as the recording date and time and all the relevant data (this is not always possible with classical systems). Our experimental results reveal that the speech watermarking procedure does not interfere in a significant way with the posterior forensic speaker identification.     

Forensic Approach to an Archaeological Casework of “Vampire” Skeletal Remains in Venice: Odontological and Anthropological Prospectus*

Abstract: During the years 2006–2007, the Archeological Superintendent of Veneto (Italy) promoted a research project on mass graves located on Nuovo Lazzaretto in Venice, where the corpses of plague deaths were buried during the 16th and 17th centuries. The burials were of different stages and are believed to be the remains of plague victims from the numerous outbreaks of pestilence, which occurred between the 15th and 17th centuries. Among the fragmented and commingled human bones, an unusual burial was found. The body was laid supine, with the top half of the thorax intact, arms parallel to the rachis axis, the articulations were anatomically unaltered. Both the skull morphology and the dimensions of the caput omeris suggest the body was a woman. A brick of moderate size was found inside the oral cavity, keeping the mandible wide open. The data collected by the anthropologist were used to generate a taphonomic profile, which precluded the positioning of the brick being accidental. Likewise, the probability of the brick having come from the surrounding burial sediment was rejected, as the only other inclusions found were bone fragments from previous burials in the same area. The data collected by the odontologist were employed for age estimation and radiological dental assessment. The forensic profile was based conceptually on the “circumstances of death” and concluded that the positioning of the brick was intentional, and attributed to a symbolic burial ritual. This ritual confirms the intimate belief held at those times, between the plague and the mythological character of the vampire.     

Arsenic Poisoning Caused by Intentional Contamination of Coffee at a Church Gathering—An Epidemiological Approach to a Forensic Investigation

Abstract: An outbreak of apparent food‐borne illness following a church gathering was promptly reported to the Maine Bureau of Health. Gastrointestinal symptoms among church attendees were initially attributed to consumption of leftover sandwiches that had been served the previous day. However, a rapid epidemiological and laboratory assessment revealed the etiology of illness, including the death of an elderly gentleman, was not food‐borne in origin. A criminal investigation determined that deliberate arsenic contamination of the brewed coffee by one of the church members was the source of the outbreak. Public health officials and criminal investigators must be aware that intentional biologic aggression can initially present as typical unintentional disease outbreaks. Practitioners must also consider the need to properly maintain and preserve potential forensic evidence. This case demonstrates the key role public health practitioners may play in criminal investigations.     

Sexual Dimorphism of the Humerus in Contemporary Cretans—A Population‐Specific Study and a Review of the Literature*

Abstract: Sex determination is the first essential step for positive identification when a decomposed body is recovered. Taking into consideration the population aspect of sexual dimorphism of the skeleton, the present study aimed to create a sex identification technique using osteometric standards, derived from a contemporary Cretan population. A total of 168 left humeri were measured according to standard osteometric techniques. The differences between the means in males and females were significant (p < 0.0005). About 92.3% of cases were correctly classified when all measurements were applied jointly. Stepwise procedure produced an accuracy rate of 92.9%. The most effective single dimension was vertical head diameter (89.9%). The current study provides standards for a population that has not been represented so far in the existing databases. It demonstrates that the humerus is an effective bone for the estimation of sex because even in a fragmentary state it can give high classification accuracy.     

DNA Preparation from Sexual Assault Cases by Selective Degradation of Contaminating DNA from the Victim

Abstract:  The standard method to purify sperm DNA from vaginal swabs taken from rape victims is to selectively digest the victim's epithelial cells to solubilize the victim's DNA, and then separate the soluble DNA from the intact sperm by centrifugation. A different approach to removing the soluble victim's DNA is to selectively degrade it using a nuclease, DNase I. DNase I reduces the amount of soluble DNA by over 1000-fold, while having virtually no effect on the sperm DNA remaining in the sperm head and inaccessible to the enzyme. Nuclease inactivation and sperm lysis then yield a soluble, pure male DNA fraction. An aliquot of soluble DNA is removed prior to nuclease addition to provide the victim's fraction. Vaginal swabs taken at defined time points following consensual sex and taken from rape victims were processed using the nuclease method or the standard method and the nuclease method gave superior short tandem repeat profiles.     

Developmental Validation of the PrepFiler™ Forensic DNA Extraction Kit for Extraction of Genomic DNA from Biological Samples*

Abstract: The PrepFiler? Forensic DNA Extraction Kit enables isolation of genomic DNA from a variety of biological samples. The kit facilitates reversible binding of DNA with magnetic particles resulting in high DNA recovery from samples with very low and high quantities of biological materials: 0.1 and 40 μL of human blood (donor 2) provided 14 and 2883 ng of DNA, respectively. Following the revised SWGDAM guidelines, performance of the developed method was investigated using different sample types including saliva on swabs, semen stains on cotton fabric, samples exposed to environment, samples with polymerase chain reaction (PCR) inhibitors, blood stains (on denim, cotton cloth, and FTA^® paper), and touch evidence‐type samples. DNA yields for all samples tested were equal or better than those obtained by both phenol–chloroform extraction and commercial kits tested. DNA obtained from these samples was free of detectable PCR inhibitors. Short tandem repeat profiles were complete, conclusive, and devoid of PCR artifacts.     

Nanomanipulation‐Coupled Nanospray Mass Spectrometry Applied to the Extraction and Analysis of Trace Analytes Found on Fibers*

Abstract: This article presents the novel instrumentation of nanomanipulation coupled to nanospray ionization‐mass spectrometry, which is used to directly probe trace analytes found on individual fibers. The low detection limits and sample volumes associated with nanospray ionization‐mass spectrometry make it the ideal instrument to implement for trace analysis. Nanospray ionization‐mass spectrometry, coupled with the nanomanipulator, allows for the direct probing of trace particulates on fibers. The technique is demonstrated by dissolving an electrostatic particle of cocaine from a fiber, collecting the analyte solution in a nanospray tip, and transferring the tip directly to the mass spectrometer to complete analysis. The utility of this technique is evident through the minimal sample preparation and short analysis time. The use of nanomanipulation coupled to nanospray ionization‐mass spectrometry could improve on current trace particulate analysis by reducing both detection limits and sample size required to complete analysis.     

Efficacy of Several Candidate Protein Biomarkers in the Differentiation of Vaginal from Buccal Epithelial Cells*

Abstract: Currently, there is no accurate method to differentiate vaginal epithelial cells from buccal epithelial cells in biological samples typically encountered in forensic casework. This study tested the expression of a selection of candidate proteins in buccal and vaginal epithelial cells. We investigated six candidate biomarkers, such as loricrin, vimentin, stratifin, cytokeratin 4, cytokeratin 13, small proline‐rich protein 2, and involucrin, using Western blot analysis on whole protein extracts and immunohistochemistry (IHC) on intact cells in an attempt to identify cell‐specific markers that would differentiate these cells by microscopy. Involucrin, loricrin, and stratifin showed differential expression during Western blot analysis and were carried through to IHC. Although proteins unique to vaginal epithelial cells and buccal epithelial cells were not identified from among the proteins tested, the increased expression levels of two proteins, loricrin and stratifin in vaginal cells, when compared to buccal cells, do provide encouraging results in the search for epithelial cell‐specific markers.     

Sex Determination Using the Second Cervical Vertebra—A Test of the Method*

Abstract: Sex is one of the critical questions addressed when unidentified skeletal remains are discovered in forensic or archeological contexts. Continuous testing and re‐evaluation of existing techniques is essential to improve accuracy and precision. The Wescott (J Forensic Sci 2000; 45 (2):462–6) method of sex determination from dimensions of the second cervical vertebra was blind‐tested on 153 adult individuals from the Spitalfields documented collection of human skeletal remains held at the Natural History Museum, London. Significant sex differences were determined for all dimensions measured (independent two‐sample t‐test, p < 0.05–0.001). The discriminant functions developed by Wescott were shown to have an overall accuracy of classification of 76.99%. Using stepwise discriminant analysis, a discriminant function based on the Spitalfields data correctly classified sex in 83.3% of individuals and was able to classify males and females with equal accuracy. Additional discriminant functions are presented for use in instances where preservation of the second cervical vertebra is poor.     

A Grass Molecular Identification System for Forensic Botany: A Critical Evaluation of the Strengths and Limitations*

Abstract: Plant material is frequently encountered in criminal investigations but often overlooked as potential evidence. We designed a DNA‐based molecular identification system for 100 Australian grasses that consisted of a series of polymerase chain reaction assays that enabled the progressive identification of grasses to different taxonomic levels. The identification system was based on DNA sequence variation at four chloroplast and two mitochondrial loci. Seventeen informative indels and 68 single‐nucleotide polymorphisms were utilized as molecular markers for subfamily to species‐level identification. To identify an unknown sample to subfamily level required a minimum of four markers or nine markers for species identification. The accuracy of the system was confirmed by blind tests. We have demonstrated “proof of concept” of a molecular identification system for trace botanical samples. Our evaluation suggests that the adoption of a system that combines this approach with DNA sequencing could assist the morphological identification of grasses found as forensic evidence.     

The Potential of X‐Ray Diffraction in the Analysis of Burned Remains from Forensic Contexts*

Abstract: In view of the difficulties in extracting quantitative information from burned bone, we suggest a new and accurate method of determining the temperature and duration of burning of human remains in forensic contexts. Application of the powder X‐ray diffraction approach to a sample of human bone and teeth allowed their microstructural behavior, as a function of temperature (200–1000°C) and duration of burning (0, 18, 36, and 60 min), to be predicted. The experimental results from the 57 human bone sections and 12 molar teeth determined that the growth of hydroxylapatite crystallites is a direct and predictable function of the applied temperature, which follows a nonlinear logistic relationship. This will allow the forensic investigator to acquire useful information about the equilibrium temperature brought about by the burning process and to suggest a reasonable duration of fire exposure.     

A Novel Approach to the Examination of Soil Evidence: Mineral Identification Using Infrared Microprobe Analysis*

Abstract: Identification of minerals using the infrared microprobe with a diamond internal reflection objective is a rapid and reliable method for forensic soil examinations. Ninety‐six mineral varieties were analyzed, and 77 were differentiated by their attenuated total reflection (ATR) spectra. Mineral grains may be mounted in oil for conventional polarized light microscope characterization and their ATR spectrum obtained with little or no interference by the liquid. This infrared microprobe method can be used to identify silicates, phosphates, nitrates, carbonates, and other covalent minerals; however, ionic minerals, metal oxide and sulfide minerals, and minerals with refractive indexes greater than diamond do not produce identifiable spectra, but the lack of a spectrum or one with high absorbance values does provide useful information. This research demonstrates the overall utility that infrared microprobe analysis brings mineral identification in soil evidence.     

Application of Raman Spectroscopy and Surface‐Enhanced Raman Scattering to the Analysis of Synthetic Dyes Found in Ballpoint Pen Inks*

Abstract: The applicability of Raman spectroscopy and surface‐enhanced Raman scattering (SERS) to the analysis of synthetic dyes commonly found in ballpoint inks was investigated in a comparative study. Spectra of 10 dyes were obtained using a dispersive system (633 nm, 785 nm lasers) and a Fourier transform system (1064 nm laser) under different analytical conditions (e.g., powdered pigments, solutions, thin layer chromatography [TLC] spots). While high fluorescence background and poor spectral quality often characterized the normal Raman spectra of the dyes studied, SERS was found to be generally helpful. Additionally, dye standards and a single ballpoint ink were developed on a TLC plate following a typical ink analysis procedure. SERS spectra were successfully collected directly from the TLC plate, thus demonstrating a possible forensic application for the technique.     

A LDR‐PCR Approach for Multiplex Polymorphisms Genotyping of Severely Degraded DNA with Fragment Sizes <100 bp*

Abstract: Reducing amplicon sizes has become a major strategy for analyzing degraded DNA typical of forensic samples. However, amplicon sizes in current mini‐short tandem repeat‐polymerase chain reaction (PCR) and mini‐sequencing assays are still not suitable for analysis of severely degraded DNA. In this study, we present a multiplex typing method that couples ligase detection reaction with PCR that can be used to identify single nucleotide polymorphisms and small‐scale insertion/deletions in a sample of severely fragmented DNA. This method adopts thermostable ligation for allele discrimination and subsequent PCR for signal enhancement. In this study, four polymorphic loci were used to assess the ability of this technique to discriminate alleles in an artificially degraded sample of DNA with fragment sizes <100 bp. Our results showed clear allelic discrimination of single or multiple loci, suggesting that this method might aid in the analysis of extremely degraded samples in which allelic drop out of larger fragments is observed.     

Juvenile and Adult Offenders Arrested for Sexual Homicide: An Analysis of Victim–Offender Relationship and Weapon Used by Race*

Abstract: Limited information is available on racial offending patterns of sexual homicide offenders (SHOs). This study used a 30‐year U.S. Supplementary Homicide Reports sample of SHOs arrested in single‐victim situations (N = 3745). The analysis strength was used to determine whether the findings yielded meaningful patterns for offender profiling. Several important findings emerged for the juvenile offenders. Juvenile White SHOs were likely to target victims with whom they shared a mutual relationship. In contrast, Black juveniles were equally likely to murder strangers and those with whom they had prior and familial relationships. Notably, no juvenile Black SHOs were arrested for murdering intimate partners. Juvenile White SHOs were twice as likely to use edged weapons as their Black counterparts. Black juveniles, conversely, were more likely than White juveniles to use personal weapons. Beyond these findings, known victim–offender relationships and weapon used may not have significant utility for investigators in identifying the SHO race, even after controlling for offender age. Limitations and future directions are discussed.     

Effects of histological staining on the analysis of human DNA from archived slides

Abstract: Archived slides of cell smears treated with histological stains for sperm detection are often the only source of DNA available when cold cases are reopened. There have been conflicting reports as to the negative effects of particular histological stains on DNA recovery and quality from human cells, making stain selection an important consideration for forensic laboratories. This study investigates the effect of several staining systems on DNA recovery from histological slide samples stored from 0 to 10 weeks. DNA profiles obtained after analysis of these samples with AmpFlSTR^® Identifiler? and increased cycle AmpFlSTR^® SGM Plus? short tandem repeat (STR) profiling systems and the effects that these stains have on DNA quantity and quality over time are described. Results indicate that Christmas Tree and Hematoxylin and Eosin stains do not have significantly different effects on DNA quality after 10‐week storage of slides. This research will assist scientists to select staining systems that have minimal deleterious effects on the DNA recovered.     

An Empirical Analysis of 30 Years of U.S. Juvenile and Adult Sexual Homicide Offender Data: Race and Age Differences in the Victim–Offender Relationship

Abstract: Little is known about the racial patterns of crimes committed by sexual homicide offenders (SHOs). This study examined race and age influences on victim–offender relationship for juvenile and adult SHOs. A large sample (N = 3868) from the Supplemental Homicide Reports (1976–2005) was used. Analyses of victim–offender patterns included examining victim age effects (child, adolescent, adult, and elderly). The findings revealed several race‐ and age‐based differences. Black offenders were significantly overrepresented in the SHO population. This finding held for juveniles and adults independently. White SHOs were highly likely to kill within their race, “intra‐racially” (range 91–100%) across four victim age categories, whereas Black SHOs killed both intra‐racially (range 24–82%) and inter‐racially (18–76%), with the likelihood of their killing inter‐racially increasing as the age of the victim increased. This study underscores the importance of considering victim–offender racial patterns in sexual murder investigations, and it offers practical implications for offender profiling.     

A Review of Forensic Science Higher Education Programs in the United States: Bachelor’s and Master’s Degrees*

Abstract: As the number of forensic science programs offered at higher education institutions rises, and more students express an interest in them, it is important to gain information regarding the offerings in terms of courses, equipment available to students, degree requirements, and other important aspects of the programs. A survey was conducted examining the existing bachelor’s and master’s forensic science programs in the U.S. Of the responding institutions, relatively few were, at the time of the survey, accredited by the forensic science Education Programs Accreditation Commission (FEPAC). In general, the standards of the responding programs vary considerably primarily in terms of their size and subjects coverage. While it is clear that the standards for the forensic science programs investigated are not homogeneous, the majority of the programs provide a strong science curriculum, faculties with advanced degrees, and interesting forensic‐oriented courses.     

Comparative Analysis of the Effects of Heat on the PCR‐Amplification of Various Sized DNA Fragments Extracted from Sus Scrofa Molars*

Abstract: This study examined the effects of heat on the amplification of DNA from the dental pulp of Sus scrofa molars and investigated the protection afforded to the pulp tissue by the dental enamel, alveolar process, and soft tissue of the head. Segments of defleshed maxilla and mandible encasing the first molar (n = 60) were subject to a range of temperatures for 15 min. Dental pulps were retrieved. Amplifications using three‐primer and four‐primer multiplexes showed no degradation of the largest fragment following exposure to 450°C. Amplifications in the three‐primer multiplex (283 bp) were successful following exposure to 525°C in maxillary samples only. This study revealed the enamel density of maxillary molars to be greater than mandibular molars in Sus scrofa. Following incineration of intact heads for 15 min (n = 10) and 1 h (n = 4) at an average temperature of 625°C, amplifications of the largest fragment (450 bp) were successful from both maxillary and mandibular teeth.