Heteroplasmy in hair: differences among hair and blood from the same individuals are still a matter of debate

The analysis of mitochondrial DNA (mtDNA) is a useful tool in forensic cases when sample contents too little or degraded nuclear DNA to genotype by autosomal short tandem repeat (STR) loci, but it is especially useful when the only forensic evidence is a hair shaft. Several authors have related differences in mtDNA from different tissues within the same individual, with high frequency of heteroplasmic variants in hair, as also in some other tissues. Is still a matter of debate how the differences influence the interpretation forensic protocols. One difference between two samples supposed to be originated from the same individual are related to an inconclusive result, but depending on the tissue and the position of the difference it should have a different interpretation, based on mutation-rate heterogeneity of mtDNA. In order to investigate it differences in the mtDNA control region from hair shafts and blood in our population, sequences from the hypervariable regions 1 and 2 (HV1 and HV2) from 100 Brazilian unrelated individuals were compared. The frequency of point heteroplasmy observed in hair was 10.5% by sequencing. Our study confirms the results related by other authors that concluded that small differences within tissues should be interpreted with caution especially when analyzing hair samples.     

A Retrospective Study of the Investigation of Homicidal Childhood Asphyxial Deaths

As one of the leading causes of traumatic deaths in newborns, infants, and young children, there is no anatomic or microscopic feature that is pathognomonic for asphyxial deaths. Instead, pathologists rely on investigation information, including confessions and/or witness statements, and potential evidence at the scene. Twenty cases of homicidal newborn, infant, and young children asphyxial deaths were reviewed, which included death and police investigation reports and autopsy reports, as well as histology slides of lung sections. This series of homicidal asphyxial deaths highlight that, in a vast majority of such cases, the final cause and manner of death rulings are dependent on confession by the perpetrator. Furthermore, this series highlights the possible role of histology to help forensic pathologists better certify asphyxial deaths. Finally, this series emphasizes important investigation points and considerations at autopsy during the investigation of asphyxial deaths in newborns, infants, and young children.     

Two Novel Methods for Enhancing Postmortem Fingerprint Recovery from Mummified Remains

Postmortem fingerprint collection is a routine part of many forensic death investigations. Although the production of postmortem prints is usually straight forward, several obstacles and scenarios can make the collection difficult. A common challenge occurs when finger pads are mummified. Several current techniques allow for softening and rehydration of mummified finger pads; however, despite the employment of such techniques, the production of adequate postmortem fingerprints can remain elusive. The authors present two techniques that can improve the chances of obtaining suitable fingerprints from mummified remains. The “baby powder method” involves applying a cornstarch‐based powder, such as baby powder, onto the darkened and mummified finger pads, to allow better visualization of the fingerprint detail. The “transillumination method” involves carefully dissecting away the tissues underlying the finger pad, followed by placement of a bright light source underneath the finger pad, such that the finger ridge pattern is illuminated.     

Can Neck Contusions in Unexplained Pediatric Deaths be Explained by Cardiopulmonary Resuscitation?

The distribution of cutaneous contusions in infants may raise the possibility of maltreatment. Neck contusions are particularly problematic since they seldom occur outside the setting of abuse, while cardiopulmonary resuscitation (CPR)‐related maneuvers may involve the neck. To address the role of CPR in neck findings, we examined 260 consecutive pediatric autopsies in which CPR was attempted. No neck contusions were identified in manners of death classified as natural, undetermined, or suicide. Contusions were present in two of 80 deaths classified as accident and had obvious accidental causes. About 26% of deaths classified as homicide had neck contusions with no explanation provided by the caregiver (p < 0.0001). In conclusion, neck contusions in deceased children with no apparent explanation should be regarded as suspicious for abuse and investigated accordingly. CPR is not a plausible explanation for neck contusions in children.     

The experience of sexual assault: findings from a statewide victim needs assessment

A statewide assessment was conducted of assaults, experiences, needs, and recommendations of 125 adult victims receiving care at 19 sexual assault centers (SACs) in the State of Maryland. More than one half of the victims (55.6%) waited years before disclosing, with delays in reporting especially likely if the assault was perpetrated by a family member (the most frequent perpetrators at 42.4% of respondents). About one half of the victims (51.3%) had been previously sexually assaulted, yet only 9% of these victims had sought treatment. The majority of respondents (69.4%) indicated they would not be filing charges against perpetrators, and of those who did, 46.2% reported dissatisfaction with the interview with police. Psychological symptoms such as depression and anxiety were the most common reasons for seeking care at the centers. Nearly all of respondents rated the care they received at the centers as very good or excellent. Respondents recommended more SACs, better advertising of their services, more mental health care within them (especially group therapy), and improved laws and law enforcement of perpetrators.     

NIST bullet signature measurement system for RM (Reference Material) 8240 standard bullets

A bullet signature measurement system based on a stylus instrument was developed at the National Institute of Standards and Technology (NIST) for the signature measurements of NIST RM (Reference Material) 8240 standard bullets. The standard bullets are developed as a reference standard for bullet signature measurements and are aimed to support the recently established National Integrated Ballistics Information Network (NIBIN) by the Bureau of Alcohol, Tobacco and Firearms (ATF) and the Federal Bureau of Investigation (FBI). The RM bullets are designed as both a virtual and a physical bullet signature standard. The virtual standard is a set of six digitized bullet signatures originally profiled from six master bullets fired at ATF and FBI using six different guns. By using the virtual signature standard to control the tool path on a numerically controlled diamond turning machine at NIST, 40 RM bullets were produced. In this paper, a comparison parameter and an algorithm using auto-and cross-correlation functions are described for qualifying the bullet signature differences between the RM bullets and the virtual bullet signature standard. When two compared signatures are exactly the same (point by point), their cross-correlation function (CCF) value will be equal to 100%. The measurement system setup, measurement program, and initial measurement results are discussed. Initial measurement results for the 40 standard bullets, each measured at six land impressions, show that the CCF values for the 240 signature measurements are higher than 95%, with most of them even higher than 99%. These results demonstrate the high reproducibility for both the manufacturing process and the measurement system for the NIST RM 8240 standard bullets.