Comparative Analysis of Insect Succession Data from Victoria (Australia) Using Summary Statistics versus Preceding Mean Ambient Temperature Models

Minimum postmortem interval (mPMI) can be estimated with preceding mean ambient temperature models that predict carrion taxon pre‐appearance interval. But accuracy has not been compared with using summary statistics (mean ± SD of taxon arrival/departure day, range, 95% CI). This study collected succession data from ten experimental and five control (infrequently sampled) pig carcasses over two summers (n = 2 experimental, n = 1 control per placement date). Linear and exponential preceding mean ambient temperature models for appearance and departure times were constructed for 17 taxa/developmental stages. There was minimal difference in linear or exponential model success, although arrival models were more often significant: 65% of linear arrival (r² = 0.09–0.79) and exponential arrival models (r² = 0.05–81.0) were significant, and 35% of linear departure (r² = 0.0–0.71) and exponential departure models (r² = 0.0–0.72) were significant. Performance of models and summary statistics for estimating mPMI was compared in two forensic cases. Only summary statistics produced accurate mPMI estimates.     

Dynamics of Ninhydrin‐Reactive Nitrogen and pH in Gravesoil During the Extended Postmortem Interval

Estimating the postmortem interval of skeletal remains is difficult, as few tools exist to do so. To address this problem, we conducted a field experiment to measure the chemistry of swine (Sus scrofa domesticus Linnaeus) gravesoil after 1 year and 3 years postmortem. Carcasses were placed on the soil surface of a pasture during June in a cold (Dfa) climate. Significant (p < 0.05) increases in ninhydrin‐reactive nitrogen, pH, total nitrogen, and nitrate in gravesoil were detected 1 year postmortem. Significant differences in gravesoil chemistry were not detected 3 years postmortem. These observations coincided with gaps in plant growth 1 year postmortem and the development of lush vegetation 3 years postmortem. We conclude that these phenomena can be used to assist the decision‐making process regarding the allocation of resources during the early stages of a death investigation.     

Temperature‐Dependent Postmortem Changes in Human Cardiac Troponin‐T (cTnT): An Approach in Estimation of Time Since Death

Estimation of time of death is an indispensible requirement of every medico‐legal autopsy, but unfortunately, there is not a single method by which it could be determined accurately. This study focused on the temperature‐dependent postmortem degradation of cardiac troponin‐T and its association with postmortem interval (PMI) in human. The analysis involved extraction of the protein, separation by denaturing gel electrophoresis (SDS‐PAGE), and visualization by Western blot using cTnT‐specific monoclonal antibodies. The area of the bands within a lane was quantified by scanning and digitizing the image using Gel Doc (Universal Hood). The results indicate a characteristic banding pattern among human cadavers (n = 6) and a pseudo‐linear relationship between percentage of cTnT degradation and the log of the time since death (r > 0.95), which can be used to estimate the postmortem interval. The data presented demonstrate that this technique can provide an extended time range during which PMI can be more accurately estimated.     

The Persistence of Sperm and the Development of Time Since Intercourse (TSI) Guidelines in Sexual Assault Cases at Forensic Science Ireland,Dublin, Ireland

The persistence of sperm using confirmatory microscopic analysis, the persistence of sperm with tails, time since intercourse (TSI) analysis, and results from the acid phosphatase (AP) reaction from approximately 5581 swabs taken from circa 1450 sexual assault cases are presented. The observed proportions of sperm in the vagina and anus declines significantly after 48 h TSI, and sperm on oral swabs were observed up to 15 h TSI. The AP reaction as a predictor of sperm on intimate swabs is questioned. All AP reaction times gave a low true positive rate; 23% of sperm‐positive swabs gave a negative AP reaction time. We show the AP reaction is an unsafe and an unreliable predictor of sperm on intimate swabs. We propose that TSI not AP informs precase assessment and the evaluative approach for sexual assault cases. To help inform an evaluative approach, TSI guidelines are presented.     

Assessment of the Role Played by N‐propanol Found in Postmortem Blood in the Discrimination Between Antemortem Consumption and Postmortem Formation of Ethanol Using Rats

This study disproves the reliability of n‐propanol as a biomarker to establish whether the ethanol found in postmortem blood is derived from antemortem ingestion or postmortem putrefactive processes. Two groups of rats were given ethanol or normal saline solution, respectively, and sacrificed 1.5 h later. After putrefaction, blood and, in a few cases, urine samples from the rats were analyzed for ethanol and n‐propanol by head‐space gas chromatography equipped with flame ionization detection. Although the concentration ratios of ethanol/n‐propanol in the postmortem blood collected from the bodies without prior alcohol consumption were expected to be <20 (as per limited case reports and previous in vitro studies), in samples from several rats that were on saline solution, this ratio was found to exceed 20. In conclusion, the concentration ratio of ethanol/n‐propanol in postmortem blood does not allow for the discernment between antemortem ingestion and the postmortem synthesis of ethanol.     

Morphoscopic Trait Expression in “Hispanic” Populations

This study evaluates population variation of eight cranial morphoscopic traits using samples of known southwest Hispanics (n = 72), Guatemalans (n = 106), American Blacks (n = 146), and American Whites (n = 218). We applied the support vector machine (SVM) method to build a prediction model based on a subsample (20%) of the data; the remainder of the data was used as a test sample. The SVM approach effectively differentiated between the four groups with correct classification rates between 72% (Guatemalan group) and 94% (American Black group). However, when the Guatemalan and southwest Hispanic samples were pooled, the same model correctly classified all groups with a higher degree of accuracy (American Black = 96%; American White = 77%; and the pooled Hispanic sample = 91%). This study also identified significant differences between the two Hispanic groups in six of the eight traits using univariate statistical tests. These results speak to the unique population histories of these samples and the current use of the term “Hispanic” within forensic anthropology. Finally, we argue that the SVM can be used as a classification model for ancestry estimation in a forensic context and as a diagnostic tool may broaden the application of morphoscopic trait data for the assessment of ancestry.     

DNA in the Criminal Justice System: The DNA Success Story in Perspective,

Current figures on the efficiency of DNA as an investigative tool in criminal investigations only tell part of the story. To get the DNA success story in the right perspective, we examined all forensic reports from serious (N = 116) and high‐volume crime cases (N = 2791) over the year 2011 from one police region in the Netherlands. These data show that 38% of analyzed serious crime traces (N = 384) and 17% of analyzed high‐volume crime traces (N = 386) did not result in a DNA profile. Turnaround times (from crime scene to DNA report) were 66 days for traces from serious crimes and 44 days for traces from high‐volume crimes. Suspects were truly identified through a match with the Offender DNA database of the Netherlands in 3% of the serious crime cases and in 1% of the high‐volume crime cases. These data are important for both the forensic laboratory and the professionals in the criminal justice system to further optimize forensic DNA testing as an investigative tool.     

Bone Mineral Density Adult Age Estimation in Forensic Anthropology: A Test of the DXAGE Application

Estimating age‐at‐death of individuals represented only by skeletonized human remains is a fundamental aspect of forensic anthropological casework. Recently, several researchers have proposed that bone mineral density (BMD) is a useful predictor of age‐at‐death in forensic contexts. Navega et al. (JFS 63(2):497–503) developed an online application called DXAGE for calculating age‐at‐death from BMD parameters. This study tests the utility of DXAGE by utilizing data from the National Health and Nutrition Examination Survey (NHANES). BMD data from a female subsample (n = 470) of the NHANES 2007–2008 dataset were analyzed, and the relationship between predicted age and real age was examined. Inaccuracy was 14.25 years, and bias was ?7.20 years. Results show that there is a weak correlation between predicted and actual age (r = 0.47) using the DXAGE application. While BMD data are potentially useful for predicting age age‐at‐death, the DXAGE application should be used cautiously in forensic anthropological contexts.     

Genetic Variants in KCNE1, KCNQ1, and NOS1AP in Sudden Unexplained Death During Daily Activities in Chinese Han Population

Fifty‐six sudden unexplained death (SUD) cases were collected from Chinese Han population, which occurred during daily activities and were autopsy negative in comprehensive postmortem autopsy. The coding exons of potassium channel genes KCNE1, KCNQ1, and nitric oxide synthase gene NOS1AP were sequenced. A synonymous mutation, KCNE1 F54F T>C was identified in 2 SUD cases, which was absent in the control subjects. Neither genotype nor allele frequencies of KCNE1 and KCNQ1 exhibited a significant difference between the SUD and control group. In contrast, the allele frequency (p = 2.7 × 10⁻¹⁰) and genotype frequency (p = 5.9 × 10⁻⁷) of rs3751284, and the genotype frequency (p = 2.9 × 10⁻²) of rs348624 in NOS1AP of SUD were significantly different from that of controls (p < 0.05). Our study suggested that rs3751284 and rs348624 might be susceptibility loci for SUD during daily activities. Larger sample sizes and further molecular studies are needed to confirm or exclude an effect of the NOS1AP SNPs on SUD risk.     

Postmortem Measurement of Human Chorionic Gonadotropin in Vitreous Humor and Bile

Abstract: Postmortem human chorionic gonadotrophin (HCG) blood assay can confirm postmortem diagnosis of pregnancy or document situations in which HCG levels are elevated. In some cases, however, blood sampling is not possible at autopsy. In this study, HCG was quantified by enzyme‐linked fluorescent assay (ELFA) in the bile (n = 5), vitreous humor (n = 4), and postmortem blood (n = 4) of five pregnant women. There were no false negatives in the pregnant subjects (n = 5) or false positives in controls (n = 34), enabling this test to be recommended for routine use in forensic contexts in which the detection of elevated HCG levels could be of interest.     

The Optimized Summed Scored Attributes Method for the Classification of U.S. Blacks and Whites: A Validation Study

Recently, Hefner and Ousley (2014) introduced the optimized summed scored attributes (OSSA) method that maximizes between‐group differences in U.S. black and white populations by dichotomizing six cranial morphoscopic trait scores. This study tests OSSA using an independent skeletal sample (Hamann‐Todd, n = 208) and positively identified forensic cases (Mercyhurst University, n = 28, and New York City Office of Chief Medical Examiner, n = 38). An evaluation of trait frequencies suggests shifting the heuristically selected sectioning point separating U.S. black and white populations from ≤ 3 to ≤ 4. We found a total correct classification of 73.0% (B = 50.9%, W = 89.2%) using the originally suggested sectioning point of ≤3, while the total correct classification increases to 79.2% (B = 80.2%, W = 78.5%) with a modified sectioning point of ≤4. With the increased total correct classification and reduced classification bias between ancestry groups, we suggest the modified sectioning point of ≤4 be used when assessing ancestry in forensic unknowns.     

Developmental validation of RSID™-Semen: a lateral flow immunochromatographic strip test for the forensic detection of human semen

Abstract: Tests for the identification of semen commonly involve the microscopic visualization of spermatozoa or assays for the presence of seminal markers such as acid phosphatase (AP) or prostate‐specific antigen (PSA). Here, we describe the rapid stain identification kit for the identification of semen (RSID?‐Semen), a lateral flow immunochromatographic strip test that uses two antihuman semenogelin monoclonal antibodies to detect the presence of semenogelin. The RSID?‐Semen strip is specific for human semen, detecting <2.5 nL of semen, and does not cross‐react with other human or nonhuman tissues tested. RSID?‐Semen is more sensitive with certain forensic evidence samples containing mixtures of vaginal secretions and semen than either of the commercially available PSA‐based forensic semen detection tests or tests that measure AP activity that were tested in parallel. The RSID?‐Semen kit also allows sampling a fraction of a questioned stain while retaining the majority of the sample for further processing through short tandem repeat analysis.     

A Comparison of the Effectiveness of Swabbing and Flossing as a Means of Recovering Spermatozoa from the Oral Cavity

This study examined whether flossing the teeth is a more effective collection method in recovering spermatozoa than conventional swabbing techniques. It was hypothesized that inclusion of flossing as a collection method would extend the recovery of spermatozoa to longer postcoital intervals (PCIs). Eighteen individuals provided 174 oral cavity samples. Successful recovery of spermatozoa was assessed with respect to the collection method and reported activity in the oral cavity during the PCI. Samples were subjected to a differential extraction procedure prior to microscopic evaluation of the extracted pellet. The results indicate that swabbing is more effective than flossing when the PCI falls within 1.5–12 h. However, spermatozoa were recovered from seven floss samples where the corresponding swabs gave negative results. When combining the results from the two collection methods, the percentage of subjects from whom spermatozoa are recovered increases for each PCI beyond the 0‐h interval.     

Citrate Content of Bone for Time Since Death Estimation: Results from Burials with Different Physical Characteristics and Known PMI

A recently introduced method to determine the postmortem interval (PMI) based on quantification of the citrate content in bone was applied on the temporal bones and femora of 20 individuals buried in wooden coffins (WO) and body bags (BB), respectively. Concerning known vs. calculated PMI, a significant difference between the temporal and the femur bone samples of the same individuals was observed in the BB group (p = 0.012). In contrast, differences were insignificant for the WO group (p = 0.400). Moreover, similar levels of underestimation of PMIs resulted from the analysis of the femora for both burial groups (p = 0.247). Also, there was consistently less citrate preserved in the flat temporal bones as compared to the femora, indicating that the cortical layer of the long bones should be preferentially employed for citrate‐based PMI estimations. The results call for additional research on subsurface‐buried and surface‐deposited remains to enhance the accuracy of the published PMI equation.     

Evaluation of Skin Surface as an Alternative Source of Reference DNA Samples: A Pilot Study

An acceptable area for collecting DNA reference sample is a part of the forensic DNA analysis development. The aim of this study was to evaluate skin surface cells (SSC) as an alternate source of reference DNA sample. From each volunteer (n = 10), six samples from skin surface areas (forearm and fingertips) and two traditional samples (blood and buccal cells) were collected. Genomic DNA was extracted and quantified then genotyped using standard techniques. The highest DNA concentration of SSC samples was collected using the tape/forearm method of collection (2.1 ng/μL). Cotton swabs moistened with ethanol yielded higher quantities of DNA than swabs moistened with salicylic acid, and it gave the highest percentage of full STR profiles (97%). This study supports the use of SSC as a noninvasive sampling technique and as a extremely useful source of DNA reference samples among certain cultures where the use of buccal swabs can be considered socially unacceptable.     

Use of prostate specific antigen in the identification of semen in postmortem cases

Over the past 20 years, the use of prostate specific antigen (PSA) as evidence of the presence of semen in forensic cases has been well established. In this study, we compared a commercially available immunoradiometric assay (IRMA) for the identification of PSA with the identification of spermatozoa in swabs obtained from the vagina of deceased females. There was agreement between the 2 methods in 67 of the 80 cases (84%), including 18 cases where both the PSA was positive and sperm were observed microscopically. The remaining cases had 1 positive result and 1 negative result. We concluded that although there was substantial agreement between the presence of sperm and a positive PSA, there were enough discrepancies between the 2 methods (16%) to justify the use of both methodologies, if possible, to make the determination of sexual activity prior to death.     

Distribution of Venlafaxine,O‐desmethylvenlafaxine,and O‐desmethylvenlafaxine to Venlafaxine Ratio in Postmortem Human Brain Tissue

Venlafaxine (VEN) and its metabolite O‐desmethylvenlafaxine (ODV) inhibit reuptake of serotonin and norepinephrine. This study examines whether VEN is differentially distributed in postmortem brain and examines relationships between brain and femoral blood concentrations from donors prescribed VEN for treatment of depression. Using high‐pressure liquid chromatography‐ultraviolet detection, VEN and ODV concentrations were measured in temporal, occipital, and cerebellar cortex of six postmortem brains. The ODV/VEN ratio was calculated as a relative measure of drug metabolism within each region where higher ratios indicated a greater conversion of VEN to ODV. Compared to the other regions examined, the cerebellum showed decreased VEN (p = 0.056), ODV (p = 0.006), and ODV/VEN (p = 0.027) ratios. In parts per million, VEN was higher in temporal and occipital cortex, but not cerebellum, as compared to femoral blood concentration. These observations suggest that VEN and ODV are differentially distributed in the brain, and metabolism of VEN to ODV may vary across brain regions.     

Corneal‐Smart Phone: A novel method to intelligently estimate postmortem interval

The changes of postmortem corneal opacity are often used to roughly estimate the postmortem interval (PMI) in forensic practice. The difficulty associated with this time estimate is the lack of objective means to rapidly quantify postmortem corneal changes in crime scenes. This study constructed a data analysis model of PMI estimation and implemented an intelligent analysis system for examining the sequential changes of postmortem corneal digital images, named Corneal‐Smart Phone, which can be used to quickly estimate PMI. The smart phone was used in combination with an attachment device that provided a darkroom environment and a steady light source to capture postmortem corneal images. By segmenting the corneal pupil region images, six color features, Red (R), Green (G), Blue (B), Hue (H), Saturation (S), Brightness (V) and four texture features Contrast (CON), Correlation (COR), Angular Second Moment (ASM), and Homogeneity (HOM), were extracted and correlated with PMI model. The results indicated that CON had the highest correlation with PMI (R² = 0.983). No intra/intersubject variation in CON values were observed (p > 0.05). With the increase in ambient temperature or the decrease in humidity, the CON values were increased. PMI prediction error was <3 h within 36 h postmortem and extended to about 6–8 h after 36 h postmortem. The correct classification rate of the blind test samples was 82%. Our study provides a method that combines postmortem corneal image acquisition and digital image analysis to enable users to quickly obtain PMI estimation.     

Parent and Metabolite Opioid Drug Concentrations in Unintentional Deaths Involving Opioid and Benzodiazepine Combinations,,

Effects of benzodiazepines on postmortem opioid parent and parent/metabolite blood concentration ratios were determined for fentanyl‐, hydrocodone‐, methadone‐, or oxycodone‐related accidental deaths. These opioids are partially metabolized by the CYP3A4 enzyme system, which is also affected by diazepam and alprazolam. Opioid/metabolite combinations examined were as follows: fentanyl/norfentanyl, hydrocodone/dihydrocodeine, methadone/EDDP, and oxycodone/oxymorphone. Parent opioid concentrations were analyzed for 877 deaths. Parent/metabolite concentration ratios were analyzed for 349 deaths, excluding cases with co‐intoxicants present known to interfere with opioid elimination. Alprazolam in combination with diazepam significantly decreased median hydrocodone concentrations by 48% (p = 0.01) compared to hydrocodone alone. The methadone parent/metabolite concentration ratio was reduced by 35% in the presence of diazepam compared to methadone alone (p = 0.03). Benzodiazepines did not statistically significantly affect fentanyl or oxycodone concentrations. Possible factors affecting opioid concentrations and possible toxicity development, including any differential effects on specific opioids, should continue to be explored.