John Schultz

Using Ground-Penetrating Radar to Locate Clandestine Graves of Homicide Victims Forming Forensic Archaeology Partnerships With Law Enforcement

Ground-penetrating radar (GPR) has become an important forensic archaeology tool used by law enforcement agencies to search for buried bodies of homicide victims. However, these agencies most often secure outside consultants to perform searches because of equipment expense and the specialized training required to operate the equipment and interpret results. This article provides a thorough discussion of GPR methodology and implementation of this technology by law enforcement agencies for clandestine body searches. The discussion provides investigators with basic knowledge of the GPR process, enabling an understanding of how the equipment is used to search for buried bodies and how investigators can secure the services of a properly trained GPR operator. Benefits of forming forensic archaeology partnerships between law enforcement agencies and academic forensic practitioners to secure GPR equipment are also discussed, with the recently established partnership between the University of Central Florida and the Orange County Sheriff’s Office as an example.

Post-cremation taphonomy and artifact preservation.

Contemporary commercial cremation is a reductive taphonomic process that represents one of the most extreme examples of postmortem human alteration of bone. The thorough reduction and fragmentation of cremated human remains often leaves little biological evidence of diagnostic value. Instead, non-osseous artifacts often provide the best evidence of the origin of the cremated remains, the identity of the decedent, and commingling of the remains of more than one individual. Once human remains have been cremated they are most commonly placed into a processor and reduced into small fragments and fine ash suitable for inurnment or scattering. The type of processor determines the size and utility of the particulates and artifacts available for analysis. The newest type of processors have changed the manner and degree of postmortem bone modification and altered the preservation of diagnostic bone fragments and cremation artifacts. This paper addresses the impact of the newest cremation procedures on forensic analysis of cremated remains.

Controlled GPR grave research: comparison of reflection profiles between 500 and 250 MHz antennae.

Since ground-penetrating radar (GPR) has become a popular search option for clandestine graves, controlled research is essential to determine the numerous variables that affect grave detection. The purpose of this study was to compare GPR reflection profiles of a controlled grave containing a large pig carcass and a blank control grave at 6 months interment in a Spodosol, which is a common soil type in Florida. Data collection was performed in perpendicular orientations over the graves using both 500 and 250 MHz antennae. Since reflection profiles are used to make initial in-field assessments during a forensic search, it is important for controlled research to evaluate this imagery option. Overall, it was possible to detect the grave containing a pig carcass at 6 months interment that was buried in a Spodosol using both the 500 and the 250 MHz antennae. While the 500 MHz antenna provided more detail within the grave containing a pig carcass, including detecting a soil disturbance and the pig carcass, the 250 MHz antenna also provided excellent imagery. Either antenna would provide optimal results for the type of soil that was sampled. Furthermore, it may be possible to locate actual forensic graves in this soil type when no response from the body is noted, as there may be a discernable response from the disturbed soil within the grave shaft and a noticeable disruption of the spodic horizon. Finally, survey orientation may also affect detection. Since data collection performed in two perpendicular directions detected the pig carcass and the grave floor of the control grave, data collection for an actual search involving a body interred for a long postmortem interval should be performed in both directions when time permits.

4 – ANALYSIS OF HUMAN CREMAINS: GROSS AND CHEMICAL METHODS

Publisher Summary This chapter provides a detailed overview of the contemporary cremation process that begins with a human body and ends with a volume of inorganic matter that can fit in a small box or an urn. It discusses various methods that cremation analysts have traditionally used to analyze cremated remains. The chapter also explores the potential of using chemical methods that help to answer some basic questions about the elemental make-up and basic properties of cremated bones and teeth. The use of chemical methods for elemental analysis is now considered to be a regular step when analyzing cremains. In particular, chemical techniques can answer some basic questions about the composition of cremains that cannot be answered from gross and microscopic methods alone. Chemical methods can be used to determine whether the disputed cremains are comprised of bones or a foreign material that was substituted for the cremains. Chemical methods may provide the only supporting evidence for the identification of cremains by detecting elevated levels of normal minor elements found in bone tissue or the presence of rare trace elements that were acquired during the decedents life.

Forensic Recovery of Human Remains: Archaeological Approaches, Second Edition

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Chemical Differentiation of Osseous, Dental, and Non-skeletal Materials in Forensic Anthropology using Elemental Analysis

Forensic anthropologists are generally able to identify skeletal materials (bone and tooth) using gross anatomical features; however, highly fragmented or taphonomically altered materials may be problematic to identify. Several chemical analysis techniques have been shown to be reliable laboratory methods that can be used to determine if questionable fragments are osseous, dental, or non-skeletal in nature. The purpose of this review is to provide a detailed background of chemical analysis techniques focusing on elemental compositions that have been assessed for use in differentiating osseous, dental, and non-skeletal materials. More recently, chemical analysis studies have also focused on using the elemental composition of osseous/dental materials to evaluate species and provide individual discrimination, but have generally been successful only in small, closed groups, limiting their use forensically. Despite significant advances incorporating a variety of instruments, including handheld devices, further research is necessary to address issues in standardization, error rates, and sample size/diversity.

Preliminary Validation of Handheld X-Ray Fluorescence Spectrometry: Distinguishing Osseous and Dental Tissue from Nonbone Material of Similar Chemical Composition†

One of the tasks of a forensic anthropologist is to sort human bone fragments from other materials, which can be difficult when dealing with highly fragmented and taphonomically modified material. The purpose of this research is to develop a method using handheld X‐ray fluorescence (HHXRF) spectrometry to distinguish human and nonhuman bone/teeth from nonbone materials of similar chemical composition using multivariate statistical analyses. The sample materials were derived primarily from previous studies: human bone and teeth, nonhuman bone, nonbiological materials, nonbone biological materials, and taphonomically modified materials. The testing included two phases, testing both the reliability of the instrument and the accuracy of the technique. The results indicate that osseous and dental tissue can be distinguished from nonbone material of similar chemical composition with a high degree of accuracy (94%). While it was not possible to discriminate rock apatite and synthetic hydroxyapatite from bone/teeth, this technique successfully discriminated ivory and octocoral.

Detecting submerged objects: The application of side scan sonar to forensic contexts

Forensic personnel must deal with numerous challenges when searching for submerged objects. While traditional water search methods have generally involved using dive teams, remotely operated vehicles (ROVs), and water scent dogs for cases involving submerged objects and bodies, law enforcement is increasingly integrating multiple methods that include geophysical technologies. There are numerous advantages for integrating geophysical technologies, such as side scan sonar and ground penetrating radar (GPR), with more traditional search methods. Overall, these methods decrease the time involved searching, in addition to increasing area searched. However, as with other search methods, there are advantages and disadvantages when using each method. For example, in instances with excessive aquatic vegetation or irregular bottom terrain, it may not be possible to discern a submersed body with side scan sonar. As a result, forensic personnel will have the highest rate of success during searches for submerged objects when integrating multiple search methods, including deploying multiple geophysical technologies. The goal of this paper is to discuss the methodology of various search methods that are employed for submerged objects and how these various methods can be integrated as part of a comprehensive protocol for water searches depending upon the type of underwater terrain. In addition, two successful case studies involving the search and recovery of a submerged human body using side scan sonar are presented to illustrate the successful application of integrating a geophysical technology with divers when searching for a submerged object.

The Contribution of Forensic Archaeology to Homicide Investigations

Collecting and processing forensic evidence during a death investigation has become an endeavor that may incorporate numerous personnel from many disciplines. During death investigations, specialized forensic experts regularly consult with law enforcement agencies at city, state, and federal levels, and with medical examiner and coroner offices. These forensic experts can also provide training, specialized laboratory analyses of forensic evidence, and services for which law enforcement may have very little or no training. Forensic archaeology is one such discipline that can provide specialized expertise at the crime scene. In addition to discussing the differences between forensic anthropology and forensic archaeology, this article presents a summary of the contributions that forensic archaeology can make during the search for and processing of crime scenes involving human remains.

Detecting buried metallic weapons in a controlled setting using a conductivity meter.

Forensic personnel may face a daunting task when searching for buried weapons at crime scenes or potential disposal sites. In particular, it is common to search for a small firearm that was discarded or buried by a perpetrator. When performing forensic searches, it is recommended to first use non-invasive methods such as geophysical instruments to minimize damage to evidence and to the crime scene. Geophysical tools are used to pinpoint small areas of interest across a scene for invasive testing, rather than digging large areas throughout the site. Prior to this project, there was no published research that tested the utility of the conductivity meter to search for metallic weapons such as firearms and blunt and sharp edged weapons. A sample comprised of 32 metallic weapons including firearms, blunt and sharp edged weapons, and scrap metals was buried in a controlled setting to test the applicability of a conductivity meter for forensic searches. Weapons were tested at multiple depths and after data collection was performed for one depth, the weapons were reburied 5 cm deeper until they were no longer detected. Variables such as weapon size, burial depth, transect interval spacing (25 and 50 cm), and metallic composition were tested. All of the controlled variables influenced maximum depth of detection. For example, size was a factor as larger weapons were detected at deeper depths compared to smaller weapons. Metal composition affected maximum depth of detection as the conductivity meter detected items comprised of ferrous metals at deeper depths than non-ferrous metals. Searches for large buried items may incorporate a transect interval spacing of 50 cm but small weapons may be undetected between transects and therefore a transect interval spacing of 25 cm is recommended. Overall, the conductivity meter is a geophysical tool to consider when searching for larger-sized metallic weapons or to use in conjunction with an all-metal detector, particularly when searching for buried metallic evidence in obstructed areas.