Supplementary pathway for vitality of wounds and wound age estimation in bruises using the electric impedance spectroscopy technique

Determination of wound vitality and estimation of wound age are central issues in daily forensic practice. The objective of this study was to develop a new and rapid method for determining wound vitality and estimating wound age in bruises using electric impedance spectroscopy. Forty Sprague-Dawley rats (140-170 g) were divided into five groups: group 1 (n=8): controls, group 2 (n=8): postmortem bruises, group 3 (n=8): bruises 1 h before death, group 4 (n=8): bruises 3 h before death, group 5 (n=8): bruises 6 h before death. Measurements of the right gluteus maximus muscle were taken at 6, 24, and 48 h after the rats were sacrificed by cervical dislocation. The results from this study indicate that electric impedance spectroscopy is clearly sensitive enough to differentiate between vital and postmortem wound infliction and to determine the survival time after the infliction of an injury.     

Fatal suicidal crossbow injury--the ability to act

We report a case of a 58-year-old man who committed suicide using a modern crossbow. The victim shot himself in the chest with a conical field-tip arrow from close proximity. We first presumed that this was a case of homicide committed with a firearm. We were, however, subsequently proved wrong. The reasons for the primary statement were as follows: the external morphology of the entrance wound being typical of a firearm discharged from long distance; the perforation found on the victim's clothing; the absence of the firearm at the place of death; the absence of the arrow in the wound. All of these reasons forced us initially to conclude that the case was one of homicide. In the reported case, the man, after having been shot with an arrow, was further able to act, even though the abdominal aorta and liver were seriously injured. While the arrow was in the wound, the injuries may not have led to massive bleeding because of incomplete tamponade of the defects by the arrow shaft. Pulling the arrow out of the victim's wound track initiated massive bleeding. Despite all these injuries, the man was capable of pulling the bow string again and reloading the crossbow with the arrow used in the first attempt. This case demonstrates that forensic investigations into crossbow injuries can be very difficult, especially when the bolt has been removed from the body.     

A comparative and comprehensive analysis of nonsexual assaults

The aim of this study was to make a comparative and comprehensive analysis of nonsexual assaults in 488 medico-legal cases presented to Forensic Medicine Outpatient Clinic of Celal Bayar University Hospital (Manisa, Turkey), between 2005 and 2009. There were blunt force injuries (BFI) in 262 cases (53.7%), sharp force injuries (SFI) in 163 cases (33.4%), and firearm-related wounds (FRW) in 63 cases (12.9%). The results showed significant differences in the monthly distribution of assaults, localization of injuries, and severity of injuries depending on the types of assaults. Most of the injuries were localized to the face, head, and neck in BFI and SFI and to the lower limbs in FRW. The results of this study will help researchers to investigate characteristics of victims, offenders, and injuries and types of assaults because of nonsexual violence.     

The use of a tunable light source (Mini-Crimescope MCS-400, SPEX Forensics) in dissecting microscopic detection of cryptic epithelial particles

As skin particles are often deposited by even a single skin contact, the detection of skin debris is important for evidence collection and DNA testing. Unfortunately, even when a dissecting microscope is used by an experienced examiner, epidermal particles are often hard to find and these traces of evidence might escape DNA analysis. Fluorescence is defined as the property of absorbing short-wavelength light and emitting longer-wavelength light. By virtue of the fluorescence characteristics of many target materials, tunable light sources assist in the macroscopic search of crime scenes and items. We combined the dissecting microscope and an alternate light source to examine the fluorescence characteristics of skin and skin particles. In a comparative study, small skin scales were hidden between sand, fibers, and soil probes, and it proved possible to search more successfully with less time and effort. On staged casework exhibits, the efficiency of the screening aid was again tested and the usability of the new procedure shown.     

The use of Polilight in the detection of seminal fluid, saliva, and bloodstains and comparison with conventional chemical-based screening tests

Biological stains can be difficult to detect at crime scenes or on items recovered from crime scenes. The use of a versatile light source may assist in their detection. The ability of Polilight to locate potential semen, saliva, and blood stains on a range of substrates and at different dilutions was tested. We also tested the use of Polilight in comparison with conventional chemical-based presumptive screening tests such as acid phosphatase (AP), Phadebas, and luminol, often used in casework for detecting potential semen, saliva, and blood stains, respectively. The Polilight was able to locate stains that were not apparent to the naked eye. The color of the material on which a stain is deposited can have an effect on the detectibility of the stain. The Polilight was found to be comparable with the AP and Phadebas tests in terms of its sensitivity. In a comparative study between the AP test and Polilight on 40 casework exhibits, one false-negative result was observed when using the Polilight. On a series of mock casework exhibits it was determined that the Polilight can be used successfully to locate saliva stains for DNA analysis. The sensitivity of luminol for detecting potential bloodstains was greater than that of Polilight; however the Polilight has particular application in instances where a bloodstain may have been concealed with paint. Overall, the Polilight is a relatively safe, simple, noninvasive, and nondestructive technique suitable for use in forensic casework.     

Ultraviolet illumination as an adjunctive aid in dental inspection

Tooth-colored resin fillings have become increasingly popular as restorative materials. Their presence in the dentition presents a challenge to the clinician and the forensic odontologist, as detection of the fillings can be difficult both visually and radiographically. As they necessarily form part of the unique dentition of an individual, recognition of the resins is important for forensic identification. Alternative light sources have been used with success in various fields of forensic science. In recent years small LED flashlights emitting at specific wavelengths in the ultraviolet light (UV) range have been developed. Their low cost, small size, and ready availability makes their use practical in both forensic dental inspection and clinical settings. UV inspection is of interest because enamel, dentin and dental materials all have differing fluorescent properties when illuminated by UV light. It was one goal of this research to quantitatively assess the fluorescence properties of modern restorative resins in order to predict their behavior during inspection using UV illumination. The second goal was to demonstrate practical use of UV in dental inspection with examples of how different materials fluoresce. Quantitative measurements were obtained for optical emission wavelength and intensity for 15 modern resins using a spectrophotometer. Results indicated that resin brands fluoresce at different wavelengths and with varying intensities. Practical use and comparison of the flashlights revealed that the most useful excitation wavelengths for resin detection were in the UVA range (365 and 380 nm). Porcelain restorations and composite resin fillings exhibited different responses to these two wavelengths and thus use of both is recommended for forensic dental inspection.     

TV tip-over morbidity and mortality in children

Twenty-eight non-fatal cases of TV related injuries were noted in San Diego in the 2 years prior to September 2008. We reviewed the scene, witness reports, past history, and autopsy findings from three fatal cases and distinguished them from abusive head trauma. The recent literature was also reviewed. Our fatal cases resulted from TVs falling on small children and causing severe head injury. The literature review showed increasing injuries and deaths relating to TV tip-over, TV stands and dressers. Most of the fatalities were head injuries in small children. The reporting methods may not be complete or accurate. Some authors in the literature review suggested preventive measures so as to decrease these injuries. Forensic scientists should become familiar with these injuries and measures so that they may communicate effectively with their communities.     

Perineal‐Vaginal Injuries in Children: Accident or Abuse?

Abstract: A large number of conditions have been mistaken for abuse. Differentiating accidental injuries from inflicted injuries is important in the management of injured children. In this work, the authors describe two cases of accidental perineal‐vaginal injury in children. In case 1, a 4‐year‐old girl suffered a vaginal tear caused by violent stretching during play; in case 2, a 3‐year‐old girl had minor lacerations of labia minora and majora. The intervention of a multi‐specialist team including a forensic pathologist and forensic psychiatrist was the key factor in being able to exclude abuse by third parties in the described cases.. This leads to the appropriate recommendations to be adopted in the forensic medicine setting.     

Investigation Delayed Is Justice Denied: Proposals for Expediting Forensic Examinations of Digital Evidence*

Abstract: There is an urgent need to reduce the growing backlog of forensic examinations in Digital Forensics Laboratories (DFLs). Currently, DFLs routinely create forensic duplicates and perform in‐depth forensic examinations of all submitted media. This approach is rapidly becoming untenable as more cases involve increasing quantities of digital evidence. A more efficient and effective three‐tiered strategy for performing forensic examinations will enable DFLs to produce useful results in a timely manner at different phases of an investigation, and will reduce unnecessary expenditure of resources on less serious matters. The three levels of forensic examination are described along with practical examples and suitable tools. Realizing that this is not simply a technical problem, we address the need to update training and establish thresholds in DFLs. Threshold considerations include the likelihood of missing exculpatory evidence and seriousness of the offense. We conclude with the implications of scaling forensic examinations to the investigation.