A New Approach for the Carbon Monoxide (CO) Exposure Diagnosis: Measurement of Total CO in Human Blood Versus Carboxyhemoglobin (HbCO)

The aim of the study is to present the application of a headspace–gas chromatography–mass spectrometry (HS‐GC‐MS) method for the determination of the carbon monoxide (CO) blood concentration and to compare it with carboxyhemoglobin (HbCO) saturation. In postmortem cases, the HbCO measured by spectrophotometry frequently leads to inaccurate results due to inadequate samples or analyses. The true role of CO intoxication in the death of a person could be misclassified. The estimation of HbCO from HS‐GC‐MS CO measurements provides helpful information by determining the total CO levels (CO linked to hemoglobin (HbCO) and CO dissociated from hemoglobin). The CO concentrations were converted in HbCO saturation levels to define cutoff blood CO values. CO limits were defined as less than 1 μmol/mL for living persons, less than 1.5 μmol/mL for dead persons without CO exposure, and greater than 3 μmol/mL for dead persons with clear CO poisoning.     

A Reliable Regression‐Based Approach for Reassociating Human Skeletal Elements of the Lower Limbs from Commingled Assemblages

Accurate sorting of commingled human remains comprises a fundamental requirement for all further anthropological analyses. The lower limb bones are particularly important for reconstructing biological profiles. This study introduces a metric technique for sorting these elements using eight standard anthropological measurements and 222 adult individuals from Greece. The bones utilized were the os coxae, the femora, the tibiae and the tali. Simple regression analyses were used to develop functions for reassociating articulating bones, providing strong correlations (r = 0.74–0.95, p‐value <0.05) and high coefficients of determination (r²=0.54–0.91). Blind tests demonstrated that combining metric and morphoscopic techniques provides an excellent sorting accuracy for the hip and knee joints (ten of ten individuals), allowing for a reliable reassociation between a sex and age indicator (os coxae) and a body size indicator (femur). Overall, these results indicate the high value of metric methods in sorting commingled human remains.     

1,2,4‐Triazine‐Based Chromogenic Reagents for the Detection of Microtraces of Various Metals Left on Human Skin*

Abstract: This article extends the application of 1,2,4‐triazine‐based chromogenic reagents to the detection of nonferrous metal traces left on contact with canvas and human skin. The possibility of detection of iron traces resulting from contact with objects made of stainless steel was investigated as well. Additionally, the ability of triazines to form chromatic complexes with Zn²⁺, Ni²⁺, Co²⁺, Cu²⁺, Cr³⁺, and Al³⁺ ions was studied spectrophotometrically. Molar absorption coefficients, ranging from 8.8 to 29.9 × 10³/M/cm, provide high sensitivity of 1,2,4‐triazines toward nonferrous ions, thus, enabling the detection at concentrations as low as a few μM. The method was sensitive enough to detect traces resulting from a 1‐min contact with a stainless steel made object, which is commonly considered as a corrosion‐resistant material. The amounts of metal ions transferred to the skin after a 2‐min contact with objects made of brass, zinc, and copper were sufficient to develop chromatic imprints.     

A Comparison of Four Presumptive Tests for the Detection of Blood on Dark Materials

Detection of blood on dark materials is difficult for crime scene examiners so presumptive tests are used to assist. This study compared the ability of luminol, leuko crystal violet, tetramethylbenzidine, and Combur Test®E to detect whole, diluted blood (1:100) and a key‐shaped blood transfer stain (1:10), on dark cotton sheeting, tea towel, socks, synthetic carpet, and car mats. Powdered bleach was used to evaluate specificity of the blood detection tests. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall misclassification rate (OMR) assessed the quality of the blood tests. Luminol was the preferred test for diluted blood having the highest sensitivity (79%–96%), NPV (66%–93%), and the lowest OMR (3%–15%). Luminol was also found to be most efficient with a testing time on 25 items of 2 h 50 min compared with up to 8 h. Overall, luminol was the most effective method, also providing information on bloodstain patterns.     

DXAGE: A New Method for Age at Death Estimation Based on Femoral Bone Mineral Density and Artificial Neural Networks

Age at death estimation in adult skeletons is hampered, among others, by the unremarkable correlation of bone estimators with chronological age, implementation of inappropriate statistical techniques, observer error, and skeletal incompleteness or destruction. Therefore, it is beneficial to consider alternative methods to assess age at death in adult skeletons. The decrease in bone mineral density with age was explored to generate a method to assess age at death in human remains. A connectionist computational approach, artificial neural networks, was employed to model femur densitometry data gathered in 100 female individuals from the Coimbra Identified Skeletal Collection. Bone mineral density declines consistently with age and the method performs appropriately, with mean absolute differences between known and predicted age ranging from 9.19 to 13.49 years. The proposed method—DXAGE—was implemented online to streamline age estimation. This preliminary study highlights the value of densitometry to assess age at death in human remains.     

A New Approach of Juvenile Age Estimation using Measurements of the Ilium and Multivariate Adaptive Regression Splines (MARS) Models for Better Age Prediction

Juvenile age estimation methods used in forensic anthropology generally lack methodological consistency and/or statistical validity. Considering this, a standard approach using nonparametric Multivariate Adaptive Regression Splines (MARS) models were tested to predict age from iliac biometric variables of male and female juveniles from Marseilles, France, aged 0–12 years. Models using unidimensional (length and width) and bidimensional iliac data (module and surface) were constructed on a training sample of 176 individuals and validated on an independent test sample of 68 individuals. Results show that MARS prediction models using iliac width, module and area give overall better and statistically valid age estimates. These models integrate punctual nonlinearities of the relationship between age and osteometric variables. By constructing valid prediction intervals whose size increases with age, MARS models take into account the normal increase of individual variability. MARS models can qualify as a practical and standardized approach for juvenile age estimation.     

A New Approach to the Investigation of Sexual Offenses—Cytoskeleton Analysis Reveals the Origin of Cells Found on Forensic Swabs*

Abstract: There are forensic inquiries in which an identification of epithelial cell types would provide important probative evidence. In cancer diagnosis, this information is yielded by histological examination of cytokeratin (Ck). Therefore, we tested 19 antibodies against different Cks (Ck1, Ck2e, Ck4, Ck5‐6, Ck7, Ck8, Ck9, CK10, Ck13, Ck14, Ck15, Ck16, Ck17, Ck18, Ck19, Ck20, Ck903, PanCkAE1_3, and CAM5‐2) on histological sections of epidermis, buccal mucosa, vaginal mucosa, penis, urogenital tract, and rectum and could identify two antigens unique to buccal‐cell and vaginal‐cell (Ck4) and skin epithelial‐cell (Ck10) cytokeratin. Subsequently, we developed an immunocytological technique for distinguishing swabbed skin and mucosal cells up to at least 1 year after sampling. By the detection of the Ck4 and Ck10 mRNAs in biopsy and laser capture microdissection collected samples via quantitative real‐time polymerase chain reaction, we were able to confirm our immunological findings. Hence, this study offers techniques to discriminate between skin and mucosal cells (buccal and vaginal) in forensic casework.     

New optimized DNA extraction protocol for fingerprints deposited on a special self-adhesive security seal and other latent samples used for human identification

Abstract: Obtaining complete short tandem repeat (STR) profiles from fingerprints containing minimal amounts of DNA, using standard extraction techniques, can be difficult. The aim of this study was to evaluate a new kit, Fingerprint DNA Finder (FDF Kit), recently launched for the extraction of DNA and STR profiling from fingerprints placed on a special device known as Self‐Adhesive Security Seal Sticker^® and other latent fingerprints on forensic evidentiary material like metallic guns. The DNA extraction system is based on a reversal of the silica principle, and all the potential inhibiting substances are retained on the surface of a special adsorbent, while nucleic acids are not bound and remain in solution dramatically improving DNA recovery. DNA yield was quite variable among the samples tested, rendering in most of the cases (>90%) complete STR profiles, free of PCR inhibitors, and devoid of artifacts. Even samples with DNA amount below 100 pg could be successfully analyzed.     

Detection of Tooth‐Colored Restorative Materials for Forensic Purposes Based on Their Optical Properties: An In Vitro Comparative Study

Victim identification using dental records involves antemortem and postmortem comparison of dental charts. Since dental restorations may be part of such records, identifying them accurately is critical. The objective of this study was to compare the diagnostic reliability and validity of two optical methods for identifying tooth‐colored restorations (digital imaging fiber optic transillumination (DiFOTI) using near infrared light, and fluorescence‐aided identification of restorations (FAIR)) with conventional diagnostic methods. Four examiners identified and charted tooth‐colored restorations in three sets of typodonts on the bench using conventional visual and tactile examination, DiFOTI (DIAGNOcam?) and FAIR. All examinations were repeated after 4 weeks. Both the sensitivity (95%) and specificity (97%) of the FAIR method were significantly higher than those for DiFOTI (82% and 82%) and for conventional inspection (71% and 82%). In conclusion, FAIR method performed better than conventional examination and DiFOTI, and was more reliable for identifying tooth‐colored restorations.     

Identification of Crystals Forming on Porcine Articular Cartilage: A New Method for the Estimation of the Postmortem Interval

Articular cartilage was examined to determine its decomposition sequence and its potential for assessing the postmortem interval. Scanning electron microscopy of articular cartilage from buried porcine trotters showed the presence of microcrystals on the synovial surface. These orthorhombic pyramidal or “coffin”‐shaped crystals, appeared at 3 weeks (22 days) after interment and disappeared after 6 weeks. The disappearance of these crystals was linked to decompositional changes to the integrity of the synovial joint. The formation and disappearance of these crystals was associated with a pH change at the cartilage surface. Scanning electron microscopy–energy‐dispersive X‐ray (SEM‐EDX) analysis showed that the five main elements contained within these crystals were carbon, nitrogen, oxygen, magnesium, and phosphorous. Such elemental analysis suggested the crystals may be struvite (MgNH₄PO₄6(H₂O)). Bacteria cultured from the cartilage synovial surface produced struvite crystals when grown in suitable media and were identified by DNA analysis to be Comamonas sp.     

First Report of Blaesoxipha plinthopyga (Diptera: Sarcophagidae) from a Human Corpse in the U.S.A. and a New State Geographic Record Based on Specimen Genotype

Carrion flies in the taxonomic family Sarcophagidae are often recovered from a human corpse. However, because such specimens are difficult to identify, the forensic literature on this taxon is quite limited compared with that of the commonly employed Calliphoridae. Faced with a sarcophagid larva that could not be identified microscopically from a death investigation in the state of Idaho, we generated cytochrome oxidase one DNA sequence data from the specimen. Comparison to a reference data set of forensically significant sarcophagids from Canada and the U.S.A. confirmed that this was the first discovery of Blaesoxipha plinthopyga in a human corpse in the U.S.A. and the first record of this species in Idaho. Because B. plinthopyga occurs from the Northern U.S.A. to the Neotropics, it is potentially useful for estimating time since death at many locations.     

Quantified Explosives Transfer on Surfaces for the Evaluation of Trace Detection Equipment

Trace explosive test surfaces are often required for the evaluation of trace detection equipment to determine the equipment performance. Test surfaces of C‐4, Detasheet, Semtex‐H, TNT, and HMTD were prepared by transferring trace amount of explosive deposited on polytetrafluoroethylene (PTFE) transfer strips onto different surfaces (Kraft paper, hard plastic, woven fabric, and soft vinyl). The amount of explosive transferred was deduced from the amount of explosive remaining on the PTFE strips after transfer, as quantified by direct analysis using tandem mass spectrometry with thermal desorption. From the data set of over 2000 transfers, we experienced lower transfer efficiency for Semtex‐H and Detasheet, and for soft vinyl and hard plastic. However, the rapid quantification mass spectrometric method allowed the transfer efficiency to be determined for all test surfaces used in an evaluation of trace explosive detectors, thereby permitting only the test surfaces with desired transfer to be accepted for the assessment.     

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.     

Ancestry and BMI Influences on Facial Soft Tissue Depths for A Cohort of Chinese and Caucasoid Women in Dunedin,New Zealand

This study measured and assessed facial soft tissue depths (FSTDs) in adult female Chinese and New Zealand (NZ) Europeans (Caucasoids). Ultrasound was used to obtain depths at nine landmarks on 108 healthy subjects (51 Chinese, 57 NZ European), erect positioned, of same age group (18–29 years). Height and weight were also recorded. Statistical analysis focused on comparison of tissue depth between the two ancestry groups and the influence of Body Mass Index (BMI) (kg/m²). Results showed mean depth differences at Supra M2 and Infra M2 landmarks significantly greater for Chinese than Caucasoid women for all three BMI Classes (BMI <20, 20 ≤ BMI < 25, 25 ≤ BMI < 30), even BMI <20. For both groups BMI positively correlated with FSTD values at all landmarks except Labrale superius. This study enabled ancestry and BMI influence on FSTDs to be observed and compared for two distinct groups. Results add to knowledge about facial tissue depth variation.     

Using Carbon,Oxygen, Strontium,and Lead Isotopes in Modern Human Teeth for Forensic Investigations: A Critical Overview Based on Data from Bulgaria

Isotopic data obtained from human remains can provide information about an individual's origin, migration, and diet. We evaluate the usefulness of carbon, oxygen, strontium, and lead isotopes for forensic investigations by comparing data from Bulgarian teeth with data from other regions. Geo‐referencing based on oxygen or strontium isotopes can be misleading due to overlap with other countries in Europe and other continents. Carbon and lead isotopes, in combination with oxygen and strontium isotopes, provide the most useful information for identification of local vs foreigner status. In particular, high‐precision Pb isotopes show a distinct “Bulgarian” range; however, it is possible that individuals from other countries in Eastern Europe and/or central to western Asia could have overlapping isotopic values. Additional high‐precision multi‐isotope data from modern humans from different regions in the world are required to transition from speculative to more quantitative estimation of a geographical place of origin for unidentified human remains.