Historical forensic pathology – a “new” discipline

Forensic Science, Medicine and Pathology -     

Challenges for forensic science: new demands in today’s world

In their 2009 report entitled ‘Strengthening forensic science in the United States: a path forward,’ the National Research Council (NRC) provided an assessment of the past, present, and future state of forensic science – especially related to impression evidence. The NRC described the need for further advances in some forensic science disciplines in order to improve criminal investigations, reduce the possibility of wrongful convictions, and to enhance national security. Recent events in international and domestic terrorism and the identification of dozens of wrongful convictions have further demonstrated the need for forensic science to address new challenges. From the bioterrorism events within the United States related to the anthrax mailings, to the seemingly endless stream of improvised explosive devices in the Iraq/Afghanistan wars, forensic science has new demands and an increasingly important opportunity to play a vital role in the world’s major events. With this demand comes a requirement to enhance the very foundations on which many disciplines in forensic science rest. The need for objective, scientifically-based criteria for determining identifications has never been more important and it will take researchers and practitioners working together to move forensic science in the proper direction.     

A new challenge in forensic toxicology exemplified by a case of murder under the influence of a synthetic cannabinoid – AM-2201

Among new psychoactive substances (NPS) available on the narcotic market, a significant number consists of synthetic cannabinoids commonly known as smokable herbal “spice” and “K2”, and which are legally treated as a legal alternative to marijuana. The dearth of information on the pharmacology of these intoxicants as they are introduced into the market has created the urgent need among healthcare providers for case studies on the substances belonging to this group, both in terms of the consequences of using such intoxicants, and in methods of detection. The subject of the present report is a multi-parameter analysis of a criminal case of an 18-year-old male who was charged with murder of his female relative and attempted murder of two other victims by stabbing. The defendant pleaded guilty, but he claimed that he had been acting without volition, because he was under the influence of the synthetic cannabinoid AM-2201, which had been purchased from a dealer as a 10 g package labelled “Mr Green – No bad trip”. Analytical methods including gas chromatography – electron ionization – quadrupole ion trap mass spectrometry (GC-EI-QIT/MS) and liquid chromatography, electrospray ionization, tandem mass spectrometry (LC-ESI-MS-MS) were developed to determine the presence of AM-2201 in the Mr Green – No Bad Trip, and in the blood of the perpetrator, respectively. Toxicological findings are discussed in the context of psychoactive and adverse physical effects resulting from the presence of AM-2201 in the human body; the observations were also analyzed in conjunction with data from the literature.     

Trust me – I'm an expert: forensic evidence and witness immunity

The implications of the NSW Court of Criminal Appeal's ruling in Commonwealth of Australia v Griffiths and Anor, to the effect that an expert who gives incorrect evidence against a party is protected from civil suit by the ‘witness immunity’ rule are reviewed. It is argued that there is an urgent need to reconsider the sanctions that may be imposed on those whose forensic evidence falls short of the high standard expected in this increasingly important area of justice.     

STR typing of human telogen hairs – a new approach

A new approach to short tandem repeat (STR) typing of DNA extracted from telogen shed hairs is presented. Newly designed primer pairs with annealing positions close to the repeat units of the STR loci HUMFES, HUMTH01 and HUMTPOX were used for amplification. The typing results were compared to those obtained by the commonly used primer pairs by means of success rates. The primer pairs capable of producing very short amplicons (<106 bp with HUMFES, <86 bp with HUMTH01 and <87 bp with HUMTPOX) described in this study significantly increased the success rates when typing telogen hairs. Received: 31 January 2000 / Accepted: 12 June 2000     

Practice of clinical forensic medicine in Sri Lanka: Does it need a new era?

Clinical forensic medicine is a sub-specialty of forensic medicine and is intimately associated with the justice system of a country. Practice of clinical forensic medicine is evolving, but deviates from one jurisdiction to another. Most English-speaking countries practice clinical forensic medicine and forensic pathology separately while most non-English-speaking countries practice forensic medicine which includes clinical forensic medicine and forensic pathology. Unlike the practice of forensic pathology, several countries have informal arrangements to deal with forensic patients and there are no international standards of practice or training in this discipline. Besides, this is rarely a topic of discussion. In the adversarial justice system in Sri Lanka, the designated Government Medical Officers practice both clinical forensic medicine and forensic pathology. Practice of clinical forensic medicine, and its teaching and training in Sri Lanka depicts unique features. However, this system has not undergone a significant revision for many decades. In this communication, the existing legal framework, current procedure of practice, examination for drunkenness, investigations, structure of referrals, reports, subsequent legal procedures, undergraduate, in-service, and postgraduate training are discussed with suggestions for reforms.     

A forensic autopsy case of death in a patient with pseudoxanthoma elasticum – Dermatopathologic findings as a clue of the cause of death

Pseudoxanthoma elasticum (PXE) is an autosomal recessive disorder, characterized by papular skin lesions and cutaneous laxity caused by fragmentation and mineralization of elastic fibers. Although vascular and retinal aspects of this disease and their associated complications are well characterized, few authors have focused on the increased incidence of epilepsy in patients with PXE. A 28-year-old Korean male was found dead in his work place with bloody-foamy discharge from his mouth and nostrils. He reportedly had a convulsive episode 5 days prior to his death in the work place. The skin showed generalized laxity and many creases with maculopapular pigmentations. A histopathologic examination of the skin revealed Pseudoxanthoma elasticum. Based on the histopathological findings and medical history, death was postulated to be due to ‘an internal cause, possibly related to a seizure attack’. Our findings suggest that histopathologic examinations of any lesions found during the forensic autopsy should be encouraged.     

DNA transfer by examination tools – a risk for forensic casework?

The introduction of profiling systems with increased sensitivity has led to a concurrent increase in the risk of detecting contaminating DNA in forensic casework. To evaluate the contamination risk of tools used during exhibit examination we have assessed the occurrence and level of DNA transferred between mock casework exhibits, comprised of cotton or glass substrates, and high-risk vectors (scissors, forceps, and gloves). The subsequent impact of such transfer in the profiling of a target sample was also investigated. Dried blood or touch DNA, deposited on the primary substrate, was transferred via the vector to the secondary substrate, which was either DNA-free or contained a target sample (dried blood or touch DNA). Pairwise combinations of both heavy and light contact were applied by each vector in order to simulate various levels of contamination.The transfer of dried blood to DNA-free cotton was observed for all vectors and transfer scenarios, with transfer substantially lower when glass was the substrate. Overall touch DNA transferred less efficiently, with significantly lower transfer rates than blood when transferred to DNA-free cotton; the greatest transfer of touch DNA occurred between cotton and glass substrates. In the presence of a target sample, the detectability of transferred DNA decreased due to the presence of background DNA. Transfer had no impact on the detectability of the target profile, however, in casework scenarios where the suspect profiles are not known, profile interpretation becomes complicated by the addition of contaminating alleles and the probative value of the evidence may be affected. The results of this study reiterate the need for examiners to adhere to stringent laboratory cleaning protocols, particularly in the interest of contamination minimisation, and to reduce the handling of items to prevent intra-item transfer.     

Applications of microbiology to different forensic scenarios – A narrative review

In contrast to other forensic disciplines, forensic microbiology is still too often considered a “side activity” and is not able to make a real and concrete contribution to forensic investigations. Indeed, the various application aspects of this discipline still remain a niche activity and, as a result, microbiological investigations are often omitted or only approximated, in part due to poor report in the literature. However, in certain situations, forensic microbiology can prove to be extremely effective, if not crucial, when all other disciplines fail. Precisely because microorganisms can represent forensic evidence, in this narrative review all the major pathological forensic applications described in the literature have been presented. The goal of our review is to highlight the versatility and transversality of microbiology in forensic science and to provide a comprehensive source of literature to refer to when needed.     

Efficacy of CBCT for assessment of impacted mandibular third molars: a review – based on a hierarchical model of evidence

A radiographic examination of mandibular third molars is meant to support the surgeon in establishing a treatment plan. For years panoramic (PAN) imaging has been the first choice method; however, where an overprojection is observed between the third molar and the mandibular canal and when specific signs suggest a close contact between the molar and the canal, CBCT may be indicated. The present review provides an evaluation of the efficacy of CBCT for assessment of mandibular third molars using a six-tiered hierarchical model by Fryback and Thornbury in 1991. Levels 1–3 include studies on low evidence levels mainly regarding the technical capabilities of a radiographic method and the diagnostic accuracy of the related images. Levels 4–6 include studies on a higher level of evidence and assess the diagnostic impact of a radiographic method on the treatment of the patient in addition to the outcome for the patient and society including cost calculations. Only very few high-evidence studies on the efficacy of CBCT for radiographic examination of mandibular third molars exist and, in conclusion, periapical or PAN examination is sufficient in most cases before removal of mandibular third molars. However, CBCT may be suggested when one or more signs for a close contact between the tooth and the canal are present in the two-dimensional image—if it is believed that CBCT will change the treatment or the treatment outcome for the patient. Further research on high-evidence levels is needed.     

Urine specimen collection following consensual intercourse – A forensic evidence collection method for Y-DNA and spermatozoa

The purpose of the prospective research was to evaluate the benefit of urine specimen as a collection technique for biological forensic evidence in adult volunteers following consensual intercourse. For detecting Y-chromosomal material Buccal Swab Spin Protocol^® was used in DNA extraction and purification and samples were analysed with Quantifiler Y Human Male DNA Quantification Kit^®. The time frame for positive Y-DNA was evaluated. Immediate microscopy for detection of spermatozoa was performed.Y-DNA was detected in 173/205 (84.4%) urine samples. Of the 86 first post-coital void urine samples available, Y-DNA was detected in 83 (96.5%) specimens. Of the 119 urine samples from volunteers with post-coital activities Y-DNA was still measurable in 70 (58.8%) urine specimens. The male DNA amount was below 0.023 ng/μl in 28/153 (18.3%) urine samples.Of the 22 urine samples obtained after 24 post-coital hours, 9 (40.9%) were still Y-DNA positive.No associations were found between coital durance, coital frequency during the past two weeks prior to the study intercourse, post-coital activities, and the urine sample Y-DNA positivity.Of the 111 urine samples where the immediate microscopy was performed, in 66 (59.5%) samples spermatozoa were verified and one sample even contained motile spermatozoa. Microscopy detected 66 (67.3%) and failed to detect spermatozoa in 32 (32.7%) of Y-DNA positive samples.In addition to conventional invasive swab techniques, urine samples seem to be an effective biological trace collection method for Y-DNA and spermatozoa within 24 h following penile-vaginal penetration. Furthermore, it may be considered as a non-invasive collection method in suspected acute child sexual abuse cases to diminish time delay in forensic evidence collection and to improve patients' positive attitudes towards evidence collection.     

Collagen degradation as a possibility to determine the post-mortem interval (PMI) of human bones in a forensic context – A survey

To find out the time since death (PMI) of a human individual, from which only skeletal remains are left is a difficult question to answer, since methods currently available don’t bring concrete answers.Subsequent to our validation study on porcine bones, we focused on human bones analysing if collagen degradation would occur at a predictive rate so that the method may be used for PMI-estimation. We tried to reproduce a method for determining the Co/NCo (Collagen to Non-Collagen) ratio of porcine bones Boaks et al. demonstrated in 2014. Our study sample consisted of 37 human bones from a forensic PMI context and 11 archaeological samples; we prepared thin bone sections of 250 µm; after staining the sections we used spectrophotometry for a portion of the samples and stereomicroscopy and digital imaging to analyze the Co/NCo ratio.Detecting the Co/NCo ratio with spectrophotometry produced results much lower than those published by Boaks et al. (2014) on porcine bone samples and much lower than physiologically expected; a similar result we also got in our validation study on porcine bone samples. We, therefore, applied our new method of stereomicroscopy and digital imaging, which we previously tested on porcine bones. The samples of male individuals showed a significant reduction of the Co/NCo ratio correlating to the PMI. Nevertheless, we still consider analyzing the Co/NCo ration of human bone samples not sufficient for forensic issues. Therefore, greater reference data as well as more experience in practice are needed.     

Smartphone-based inertial sensors technology – Validation of a new application to measure spatiotemporal gait metrics

BackgroundSmartphones are increasingly recognized as the future technology for clinical gait assessment.ResearchQuestion: To determine the concurrent validity of gait parameters obtained using the smartphone technology and application in a group of patients with musculoskeletal pathologies.MethodsPatients with knee, lower back, hip, or ankle pain were included in the study (n = 72). Spatiotemporal outcomes were derived from the walkway and the smartphone simultaneously. Pearson’s correlations and limits of agreement (LoA) determined the association between the two methods.ResultsCadence and gait cycle time showed excellent correlation and agreement between the smartphone and the walkway (cadence: r = 0.997, LoA=1.4%, gait cycle time: r = 0.996, LoA = 1.6%). Gait speed, double-limb support and left and right step length demonstrated strong correlations and moderate agreement between methods (gait speed: r = 0.914, LoA=15.4%, left step length: r = 0.842, LoA = 17.0%, right step length: r = 0.800, LoA=16.4%). The left and right measures of single-limb support and stance percent showed a consistent 4% bias across instruments, yielding moderate correlation and very good agreement between the smartphone and the walkway (r = 0.532, LoA = 9% and r = 0.460, LoA=9.8% for left and right single-limb support; r = 0.463, LoA = 5.1% and r = 0.533, LoA = 4.4% for left and right stance).Significance: The examined application appears to be a valid tool for gait analysis, providing clinically significant metrics for the assessment of patients with musculoskeletal pathologies. However, additional studies should examine the technology amongst patients with severe gait abnormalities.     

Application and performance of artificial intelligence technology in forensic odontology – A systematic review

Forensic odontology (FO) mainly deals with the identification of the individual through the remains, which mainly includes teeth and jawbones. Artificial intelligence (AI) technology has proven to be a breakthrough in providing reliable information in decision making in forensic sciences. This systematic review aimed to report on the application and performance of AI technology in FO. The data was gathered through searching for the articles in the renowned search engines, which have been published between January 2000 - June 2020. QUADAS-2 was adopted for the risk of bias analysis of the included studies. AI technology has been widely applied in FO for identifying bite-marks, predicting mandibular morphology, gender determination, and age estimation. Most of these AI models are based on either artificial neural networks (ANNs) or convolutional neural networks (CNNs). The results of the studies are promising. Studies have reported that these models display accuracy and precision equivalent to that of the trained examiners. These models can be promising tools when identifying victims of mass disasters and as an additive aid in medico-legal situations.     

Developmental validation of the Microreader™ RM-Y ID System: a new rapidly mutating Y-STR 17-plex system for forensic application

International Journal of Legal Medicine - Y-chromosomal short tandem repeats (Y-STRs) are widely applied to evolutionary, genealogical, and kinship analyses of male linages in forensic studies, but...     

A case of intoxication with a new cathinone derivative α-PiHP – A presentation of concentrations in biological specimens

IntroductionCathinones are currently the second largest and the second most frequently seized group of new psychoactive substances (NPS). One of the most recent synthetic cathinones that has appeared on the ‘legal highs’ market is alpha-pyrrolidinoisohexanophenone (α-PiHP).Case historyAn 18-year-old man was found dead in an apartment. The autopsy materials were collected for toxicological analyses.MethodsThe quantitative analyses were carried out by LC-MS/MS.Resultsα-PiHP was detected and quantified in all post-mortem materials except the hair. The determined concentrations of the compound in the blood, urine and bile were 69 ng/mL, 2072 ng/mL, and 341 ng/mL respectively. The concentrations of α-PiHP in solid tissues were in the range of 7–478 ng/g. 4-Chloromethcathinone (4-CMC), N-ethylhexedrone, benzoylecgonine and 3,4-methylenedioxymethamphetamine (MDMA) were also detected in some materials.DiscussionNo cases presenting concentrations of α-PiHP in biological materials have been reported so far. Due to the similarity of structures and the reported dosages, an attempt to compare the concentrations of α-PVP and α-PHP has been made. In the described case, functional death through intoxication of α-PiHP was accepted as the final cause of death. The other detected substances did not contribute to death due to their very likely distant administration.Conclusionα-PiHP is another new synthetic cathinone that is a danger to the life of users. The described fatal intoxication case presents the concentrations of α-PiHP in post-mortem materials. This data could be valuable for further interpretation of other results from toxicological analyses in cases where the use of α-PiHP is suspected.