Canid scavenging/disarticulation sequence of human remains in the Pacific Northwest

Greater understanding of animal scavenging of human remains can assist forensic science investigators in locating and recovering dispersed skeletal elements, in recognizing damage produced by scavengers, and in making more informed estimates of the postmortem interval. The pattern of skeletal damage can indicate whether the body was scavenged while intact or at some time after other natural processes of disarticulation had begun. This study analyzed thirty partially to fully skeletonized human remains with respect to scavenging at the time of body discovery in order to determine if a patterned consumption sequence existed. The scavengers were primarily coyotes (Canis latrans) and domestic dogs (C. familiaris). Sixteen non-carnivore-scavenged remains were also examined and contrasted with the carnivore-scavenged sample. Observed postmortem intervals from death to recovery ranged from 4 h to 52 months. Results demonstrate that canid scavenging of human remains takes place in sequential stages: Stage 0 = no bony involvement; Stage 1 = ventral thorax damaged and one or both extremities removed; Stage 2 = lower extremity involvement; Stage 3 = only vertebral segments remain articulated; and Stage 4 = total disarticulation. Results revealed a clear correspondence between stages of disarticulation and the postmortem interval.     

Managing commingled remains from mass graves: considerations, implications and recommendations from a human rights case in Chile

This paper focuses on a little discussed part of Chilean history and the efforts to resolve Human Rights cases from the period 1973 to 1990. A case file is presented to illustrate the different stages, problems and solutions found in one particularly challenging case studied by the Special Unit of Identification of Detained and Missing (UEIDDDD) of the Human Rights Program of the Forensic Service, Chile, during the period 2006-2009. A major complication found in this example was the fact that the remains studied were commingled, and in addition, were mixed with remains that were not of medico-legal interest - deposited prior to and after the case in question, but within the same common grave. Multiple burials and the consequences of commingled skeletal human remains are reviewed, paying special attention to the roles that different agents related to these types of cases play, how they influence the decision making process and the outcomes that can be expected in commingled cases due to the complexities and challenges they present. Effective communication between prosecutors and forensic practitioners is vital to optimize the resources. Equally important is the relationship that is built between the practitioners and the victims' families regarding communication, information and expectations that both parties may have.     

Osteometric sorting of commingled human remains

This paper describes the method of osteometric sorting. Osteometric sorting is the formal use of size and shape to sort bones from one another. The method relies heavily on measurement data and statistical models and is designed to maximize objectivity. The goal of this paper is to validate the use of osteometric sorting and to provide case examples of its utility. Selected regression models are also presented for use with osteometric sorting. We advocate this technique as one tool among many in the anthropologist's toolkit for sorting commingled skeletal remains.     

A method for defleshing human remains using household bleach

Medical examiners and forensic anthropologists are often faced with the difficult task of removing soft tissue from the human skeleton without damaging the bones, teeth and, in some cases, cartilage. While there are a number of acceptable methods that can be used to remove soft tissue including macerating in water, simmering or boiling, soaking in ammonia, removing with scissors, knife, scalpel or stiff brush, and dermestid beetles, each has its drawback in time, safety, or potential to damage bone. This technical report using the chest plate of a stabbing victim presents a safe and effective alternative method for removing soft tissue from human remains, in particular the chest plate, following autopsy, without damaging or separating the ribs, sternum, and costal cartilage. This method can be used to reveal subtle blunt force trauma to bone, slicing and stabbing injuries, and other forms of trauma obscured by overlying soft tissue. Despite the published cautionary notes, when done properly household bleach (3-6% sodium hypochlorite) is a quick, safe, and effective method for examining cartilage and exposing skeletal trauma by removing soft tissue from human skeletal remains.     

Decomposition chemistry of human remains: a new methodology for determining the postmortem interval

This study was conducted to characterize the chemistry associated with the decomposition of human remains with the objective of identifying time-dependent biomarkers of decomposition. The purpose of this work was to develop an accurate and precise method for measuring the postmortem interval (PMI) of human remains. Eighteen subjects were placed within a decay research facility throughout a four-year time period and allowed to decompose naturally. Field autopsies were performed and tissue samples were regularly collected until the tissues decomposed to the point where they were no longer recognizable (encompassing a cumulative degree hour (CDH) range of approximately 1000 (approximately 3 weeks)). Analysis of the biomarkers (amino acids, neurotransmitters, and decompositional by-products) in various organs (liver, kidney, heart, brain, muscle) revealed distinct patterns useful for determining the PMI when based on CDHs. Proper use of the methods described herein allow for PMIs so accurate that the estimate is limited by the ability to obtain correct temperature data at a crime scene rather than sample variability.     

Cocaine in decomposed human remains.

From March 1988 through March 1990, at the Philadelphia Medical Examiner's Office toxicology laboratory, samples from 77 decomposed human bodies were tested for the presence of cocaine, employing gas chromatography/mass spectrometry (GC-MS). The material analyzed included decomposed soft tissue, bloody decomposition fluid, mummified tissue, maggots, and beetle feces. Twenty-two cases (28.6%) were positive for cocaine, many of these cases in states of advanced decomposition. These findings indicate the usefulness of testing decomposed tissue for cocaine in all cases where its presence is suspected. This is contrary to what might be expected, since cocaine is generally labile and rapidly broken down by both enzymatic and nonenzymatic mechanisms.     

Spatial patterning of vulture scavenged human remains

This article presents the results of a pilot study on the effects of vulture modification to human remains. A donated body from the Willed Body Donation Program was placed at the Forensic Anthropology Research Facility (FARF), an outdoor human decomposition laboratory located at Texas State University-San Marcos. The effects of vulture scavenging on the timing and sequence, and the rate of skeletonization, disarticulation, and dispersal were observed via a motion sensing camera and direct observation. Using GIS (Geographic Information Systems) and GPS (Global Positioning System) technologies and spatial analytical methods, the transport of skeletal elements was mapped in order to analyze dispersal and terrain-influenced patterns of active vulture scavenging. Results showed that the initial scavenging took place 37 days after placement at FARF. This delay in scavenging differs from previous research. After the initial appearance of the vultures, the body was reduced from a fully-fleshed individual to a skeleton within only 5h. This underscores the potential for errors in postmortem interval estimations made at vulture scavenged scenes. Additionally, spatial analysis showed that skeletal elements were dispersed by vultures to lower elevations, and that the disarticulation and dispersal of the skeletal elements occurs early in the scavenging sequence.     

Odor analysis of decomposing buried human remains

This study, conducted at the University of Tennessee's Anthropological Research Facility (ARF), lists and ranks the primary chemical constituents which define the odor of decomposition of human remains as detected at the soil surface of shallow burial sites. Triple sorbent traps were used to collect air samples in the field and revealed eight major classes of chemicals which now contain 478 specific volatile compounds associated with burial decomposition. Samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and were collected below and above the body, and at the soil surface of 1.5-3.5 ft. (0.46-1.07 m) deep burial sites of four individuals over a 4-year time span. New data were incorporated into the previously established Decompositional Odor Analysis (DOA) Database providing identification, chemical trends, and semi-quantitation of chemicals for evaluation. This research identifies the "odor signatures" unique to the decomposition of buried human remains with projected ramifications on human remains detection canine training procedures and in the development of field portable analytical instruments which can be used to locate human remains in shallow burial sites.     

Recovery of human remains after shark attack

Two cases of fatal shark attack are reported where the only tissues recovered were fragments of lung. Case 1: An 18-year-old male who was in the sea behind a boat was observed by friends to be taken by a great white shark (Carcharodon carcharias). The shark dragged him under the water and then, with a second shark, dismembered the body. Witnesses noted a large amount of blood and unrecognizable body parts coming to the surface. The only tissues recovered despite an intensive beach and sea search were 2 fragments of lung. Case 2: A 19-year-old male was attacked by a great white shark while diving. A witness saw the shark swim away with the victim's body in its mouth. Again, despite intensive beach and sea searches, the only tissue recovered was a single piece of lung, along with pieces of wetsuit and diving equipment. These cases indicate that the only tissue to escape being consumed or lost in fatal shark attacks, where there is a significant attack with dismemberment and disruption of the integrity of the body, may be lung. The buoyancy of aerated pulmonary tissue ensures that it rises quickly to the surface, where it may be recovered by searchers soon after the attack. Aeration of the lung would be in keeping with death from trauma rather than from drowning and may be a useful marker in unwitnessed deaths to separate ante- from postmortem injury, using only relatively small amounts of tissues. Early organ recovery enhances the identification of human tissues as the extent of morphologic alterations by putrefactive processes and sea scavengers will have been minimized. DNA testing is also possible on such recovered fragments, enabling confirmation of the identity of the victim.     

Teeth as a source of DNA for forensic identification of human remains: A Review

Teeth and bones are frequently the only sources of DNA available for identification of degraded or fragmented human remains. The unique composition of teeth and their location in the jawbone provide additional protection to DNA compared to bones making them a preferred source of DNA in many cases. Despite this, post-mortem changes in the structure and composition of teeth, and the location and diagenesis of DNA within them are poorly understood. This review summarises current knowledge of tooth morphology with respect to DNA content and preservation, and discusses the way in which post-mortem changes will affect the recovery of DNA from teeth under a range of commonly used extraction protocols. We highlight the benefits and pitfalls of using specific tooth tissues for DNA extraction and make recommendations for tooth selection and sampling that will maximise DNA typing success. A comprehensive understanding of tooth structure and an appreciation of the relationship between DNA and mineralized tissues in post-mortem teeth are critical for optimal sample selection. More informed sampling methods that target specific tooth tissues will increase the likelihood of successful genetic analysis and allow for efficient and timely missing persons case work and disaster victim identification response.     

Analysis of human remains recovered from a shark

Trauma caused by marine scavengers and predators, especially sharks, is not well known. This paper describes the effect of shark attack on human remains. They were found in the stomach of a tiger shark caught by fishermen near Hollywood Beach, Florida. The remains belonged to a white male in his late twenties or early thirties with a stature of 175 cm. The damages to the skeleton and the association of these damages with the behaviours of tiger sharks is also analyzed. The trauma affecting long bones are circular punctures around the epiphyseal ends. Other changes include unique crescent shape grooves horizontal to the shaft of the bone. Although all of the bones are affected, none of them is fractured or crushed, suggesting that the body parts are first dismembered and then swallowed and digested.     

Anthropological and radiographic comparison of vertebrae for identification of decomposed human remains

This case study demonstrates the importance of involving an anthropologist in forensic situations with decomposed remains. Anthropological consultation was used in conjunction with the comparison of antemortem and postmortem radiographs to establish positive identification of unknown, decomposed remains. The remains had no traditional identifying features such as fingerprints or dental. Through anthropological analysis, it was determined the decedent was male, between 20 and 23 years at time of death and c. 5'2' tall. This information allowed for a presumptive identification and a request for antemortem radiographs. The missing person was identified comparing the spinous processes of the cervical and thoracic vertebrae between ante- and postmortem radiographs.     

Evaluation and identification of dismembered human remains.

On occasion, pathologists are confronted with cases involving dismembered human remains. Such cases present unique and interesting problems of postmortem identification. Four cases involving dismembered human remains are presented here and practical suggestions on how identification can be achieved are provided.     

The need for a complete dental autopsy of unidentified edentulous human remains

In December 2017, a decomposed unidentified body was found near the river Tronto in Teramo, Italy. The corpse was found without any identifying documents or specific personal belongings, except for a packet of cigarettes. The medical examiner determined a gastric perforation from the intake of hydrochloric acid to be the cause of death. A jar of muriatic acid found near the body led to suicide being considered the manner of death. The Penal Court in Teramo appointed two forensic odontologists to complete the postmortem assessment and collect dental data for personal identification. The corpse was found wearing a complete set of upper and lower dentures. The dental autopsy and 42 periapical X-ray images helped generate a biological profile of a man totally edentulous with upper and lower dentures, as well as an osteosynthesis with two plates and screws in the left ascending ramus of the mandible. In March 2018, the sister of a missing person reported the disappearance of her brother, and a presumptive identification was performed through visual recognition of the decomposed body. The sister confirmed the presence of two dentures and the location of the maxillo-facial surgery for the treatment of the fractured mandible. A complete dental autopsy was able to establish his identity without any DNA comparison needed. This case highlights the importance of performing a complete dental autopsy inclusive of dental radiographs, and its value in the identification of all unknown human remains even when totally edentulous.A complete dental autopsy should be performed in all cases of human identification.

Keypoints

• Despite a corpse being edentulous, a complete dental autopsy can still be useful.
• Dental radiographs, such as bitewings, periapical images, panoramic radiographs, and CT scans, are recommended in all identification autopsies.