Forensic Toxicology

Forensic Toxicology

Forensic toxicology is the analysis of biological samples for the presence of toxins, including drugs. The toxicology report can provide key information as to the type of substances present in an individual and if the amount of those substances is consistent with a therapeutic dosage or is above a harmful level. These results can be used to make inferences when determining a substance's potential effect on an individual's death, illness, or mental or physical impairment. For example, the results of a blood analysis from a driver involved in a car accident can be used to determine if the individual was under the influence of drugs or alcohol.

Forensic toxicology is a continually advancing discipline. New drugs are always being developed, which creates a constant need to design novel approaches for their detection. To rise to this challenge, new instrumentation is being used and new detection methods are constantly in development.

NIJ seeks to fund research to:

  • Improve tools and technologies to better identify, collect, preserve and analyze biological samples to show the presence of drugs and other substances in a person.

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Forensic Human Hair Examination Guidelines

1. Introduction

Hair examinations and comparisons, as generally conducted by forensic scientists, often provide important investigative and associative information. Human and animal hairs have been used in forensic investigations for over a century. Reports abound in the literature concerning the use of human and animal hairs encountered in forensic casework. These guidelines represent a recommended procedure for the forensic examination, identification, and comparison of human hair. Hairs are readily available for transfer, easily transferred, and resilient. Hair examination may be used for associative and investigative purposes and to provide information for crime scene reconstruction. The ability to perform a forensic microscopical hair comparison is dependent on a number of factors.

  • These factors include the following:
  • Whether an appropriate known hair sample is representative.
  • The range of features exhibited by the known hairs.
  • The condition of the questioned hair.
  • The training and experience of the hair examiner.
  • The usage of the appropriate equipment and methodology.
  • DNA analysis can be performed on hair but should be performed only after an initial microscopical assessment. A full and detailed microscopical comparison with possible known sources of

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Case Report On The Identification Of A Murder Victim By Forensic Dental Techniques

Introduction

Case Report

One of the common methods of identifying unknown dead persons is by confrontation identification. This method is used by the police on the basis of a presumed identity of the body, which a relative or someone else subsequently visually confirms when confronted with the face or the general appearance of the dead person's body and clothes. The facial features can also be compared with a past photograph or other identity cards. However, if the body is damaged in some manner, be it by fire or simple putrefaction, the facial features may be missing and then other features or characteristics have to be used. One such feature is the anatomy of the frontal sinus according to a posterior-anterior radiograph. But a dental identification is usually easier to perform, since radiographs are only infrequently unavailable, because most people are likely to have visited their dentists at least once and had radiographs taken of the teeth. Moreover, teeth are the hardest tissue of the body and can resist...

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Forensic Determination Of Age At Time Of Death From The Analysis Of Bones

Forensic determination of ‘age at time of death’ from the analysis of bones Dr Peter Zioupos at Cranfield University has developed an improved method for determining a person’s age at the time of death, from small samples of bone and with a level of accuracy previously not obtainable. The technique is particularly effective beyond the age of skeletal maturity (30-35 years), an area that is very often problematic with existing techniques. The university is seeking collaborative development and licensing relationships with commercial/research partners. This invention from Cranfield University consists of a technique for the prediction of ‘age at death’ using laboratory based analytical techniques. Age is one of the four important attributes that a forensic anthropologist may be called on to determine in the case of a body or body parts of unknown origin, together with sex, stature and ethnic background. Current methods of age determination are largely qualitative and are only able to categorise individuals within broad age bands. The accuracy of current age determination methods...

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The Effects Of Temperature On The Decomposition Rate Of Human Remains

Forensic anthropologists are frequently called upon to assist in the recovery and analysis of recently-deceased individuals. Estimating postmortem interval, or PMI, is an important part of a forensic anthropologist's job. The PMI serves two functions. First, estimating PMI can narrow down the potential pool of missing persons and ultimately help to identify the remains. Second, in homicide cases, law enforcement personnel use the PMI to exclude possible assailants. Forensic scientists use many methods to estimate the PMI, but anthropologists tend to emphasize the decay and decomposition of soft tissues. Qualitative "stages" of decomposition that broadly correspond to the PMI have served as rough guides for most estimates made by anthropologists. However, nearly all previous studies have considered decomposition as a thing to be described, not as a process to be scored and used statistically to estimate the PMI. Forensic anthropology might benefit from applying quantitative methods to the study of decomposition. Fly larvae (maggots) associated with decomposing remains grow and develop at a rate...

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The Effect of Various Coverings on the Rate of Human Decompositioin

Abstract

A multitude of factors can affect the decomposition process, increasing or decreasing its rate. Some of the most frequently observed variables are temperature, moisture, insect activity, and sun or shade exposure. Coverings can impact the decomposition process, and are found frequently in forensic cases. In a survey of New Mexico cases, Komar (2003) reported that sixteen individuals were found wrapped in plastic, and twenty were noted as wrapped in a cloth or blanket. In a survey conducted of eighty-seven cases, fifty-four of the bodies were wrapped in some type of covering. Plastic was most common, but a variety was noted, including rugs, sleeping bags, and blankets, (Manhein, 1997). In order to document how coverings affect early decomposition an experiment was designed to mimic a forensic setting. Three human cadavers were used in each of two repetitions of this experiment. Two of the cadavers were covered, one in plastic tarp, the other in a cotton blanket, while the third was left uncovered as a control...

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Forensic Entomology Decay

Forensic entomology is the study of insects for medico-legal purposes. There are many ways insects can be used to help solve a crime, but the primary purpose of forensic entomology is estimating time since death.Once a person dies his or her body starts to decompose. The decomposition of a dead body starts with the action of microorganisms such as fungi and bacteria, followed by the action of a series of insects (arthropods). Bodies decompose slowly or fast depending on weather conditions, if they have been buried or are exposed to the elements, if there is presence of insects or if they have a substance in their bodies that prevents their fast decomposition such as body size and weight, clothing,The dead body goes through constant changes allowing investigators to estimate how long that person has been dead. Generally speaking, there are 5 basic stages of decomposition:Fresh, putrefaction, fermentation, dry decay and skeletonization. Every stage attracts different kinds of organisms...

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Effect Of Alcohols On Decomposition Temperature Of Chloroform Hydrate

INTRODUCTION

In connection with the work being done on hydrocarbon hydrates in the physical chemistry laboratories of the University of Oklahoma, it became desirable to know what effect 2-propanol m1Iht have on the decomposition temperature of chloroform hydrate. The decomposition effect for ethanol had been 'determined by sampson (6).

Deaton and Prost (2) report the use of alcohols as inhibltors of hydrate formation In high-pressure natural las Unes. Alcohols are Injected into the Une to decompose any hydrate present or to inhibits formation and subsequent closure of the pipes by solid hydrate.

In some preliminary experiments with the l)'Stem water-chlorotorm-2- propanol, the question arose as to Whether or not 2-propanol would form a hydrate or inhib1its formation. Bampeon (6) had determined the decomposltion effect ethanol had on chloroform hydrate. Since literature searches and current investigations have indicated that ethanol does not form a lattice type hydrate, it was assumed that a...

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Decompositional Odor Analysis Database – Phase I

ABSTRACT: This study, conducted at the University of Tennessee’s Anthropological Research Facility (ARF), describes the development of the Decompositional Odor Analysis (D.O.A.) Database and seeks to establish the chemical basis for canine’s scenting ability when detecting human remains. This database is composed of chemicals that are liberated during the decompositional process from buried human remains. This ‘living’ database currently spans the first year and a half of burial, providing identification, chemical trends and semi-quantitation of chemicals liberated below, above and at the surface of 1.5 – 2.5 ft graves for three individuals (two males and one female). A fourth male individual (buried in 1990) was also sampled to provide possible ‘endpoint’ information. In-ground, in-corpse thermocouples provided temperature information which can be used to correlate accumulated degree days (ADDs) to surface decompositional events and indicated an approximate 12 hour lag between equilibration of grave temperature with the surface air. Clear, sealed, hollow pipes were also placed in the grave vault providing viewing ports by which the burial...

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Decomposition And Insect Succession On Cadavers Inside A Vehicle Environment

Abstract

This study presents differences in rate of decomposition and insect succession between exposed carcasses on the soil surface and those enclosed within a vehicle following carbon monoxide (CO) poisoning. Nine 45-kg pigs were used as models for human decomposition. Six animals were sacrificed by CO gas, half of which were placed within the driver’s side of separate enclosed vehicles and half were placed under scavenger-proof cages on the soil surface. A further three animals were sacrificed by captive head bolt and placed under scavenger proof cages on the soil surface. The pattern of insect succession and rate of decomposition were similar between surface carcasses within trials regardless of the mode of death. Progression through the physical stages of decomposition was 3–4 days faster in the enclosed vehicle due to higher temperatures there compared to external ambient temperatures. Patterns of insect succession also differed between the vehicle and surface treatments. Carcass attendance by representatives of the Calliphoridae was delayed within the vehicle environment by 16–18 h, while oviposition...

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Beyond The Grave – Understanding Human Decomposition

Human decomposition begins approximately 4 minutes after death has occurred. The onset is governed by a process called autolysis – or self-digestion. As cells of the body are deprived of oxygen, carbon dioxide in the blood increases, pH decreases and wastes accumulate which poison the cells. Concomitantly, unchecked cellular enzymes (lipases, proteases, amylases, etc.) begin to dissolve the cells from the inside out, eventually causing them to rupture, and releasing nutrient-rich fluids. This process begins and progresses more rapidly in tissues that have a high enzyme content (such as the liver) and a high water content such as the brain, but eventually affects all the cells in the body. Autolysis usually does not become visually apparent for a few days. It is first observed by the appearance of fluidfilled blisters on the skin and skin slippage where large sheets of skin slough off the body. Meanwhile, the body has acclimated to ambient temperature (algor mortis), blood has settled in the body causing discoloration of the skin...

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Analytical Separations Of Mammalian Decomposition Products For Forensic Science: A Review

Abstract

The study of mammalian soft tissue decomposition is an emerging area in forensic science, with a major focus of the research being the use of various chemical and biological methods to study the fate of human remains in the environment. Decomposition of mammalian soft tissue is a postmortem process that, depending on environmental conditions and physiological factors, will proceed until complete disintegration of the tissue. The major stages of decomposition involve complex reactions which result in the chemical breakdown of the body’s main constituents; lipids, proteins, and carbohydrates. The first step to understanding this chemistry is identifying the compounds present in decomposition fluids and determining when they are produced. This paper provides an overview of decomposition chemistry and reviews recent advances in this area utilising analytical separation science.

1. Introduction

The study of mammalian soft tissue decomposition is an emerging area in forensic science, with a major focus of the research being the use of various chemical and biological methods to study the fate of human remains in the environment. Such techniques have major roles to play in locating clandestine gravesites assisting in the estimation of postburial interval...

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Forensic DNA Identification from Human Remains Submerged in Water

ABSTRACT: We describe the successful identification of the remains of a saponified body found in a dam by typing of nuclear DNA. Whereas DNA extracted from soft tissues yielded negative PCR results, DNA extracted from the bone by a slightly modified Qiagen procedure allowed the typing of sex (AMG locus) and of 10 additional STR loci. An identity document was found belonging to a man missing for 3 years and comparison of the results to the DNA profiles of his son and wife confirmed the identity. The longest delay reported until now for successful nuclear DNA genotyping after immersion in river water was 18 months. This case demonstrates a delay of up to 3 years.

Recovery of human DNA from bones of severely decomposed bodies was reported for the identification of unidentified bodies like murder victims (1) or ancient human remains (2). Nevertheless, few studies concern genotyping of bodies immersed in water,the longest reported delay for successful identification being...

Additional Resource: Skeletal Remains Presumed Submerged in Water for Three Years Identified Using PCR-STR Analysis (20 downloads)

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Dilemma for Autopsy Surgeon

Introduction:

Forensic medicine is best learned by a judicious combination of theoretical and practical knowledge. A good forensic expert is one who has not merely a vast experience in conducting autopsies, but one who has trained himself to make precise and correct interpretation of the findings. One must not allow dogmatism or inflexibility to cloud one’s judgment. A self- opinionated expert is a poor expert. There are several inherent pitfalls that must be avoided in the course of medicolegal autopsies which can lead to erroneous or fallacious conclusions. Every forensic pathologist must familiarize himself with these postmortem artefacts that are liable to misinterpretation. Postmortem Artefacts are due to any change caused or features introduced in a body after death. The artefacts are physiologically unrelated to the natural state of the body or tissues or the disease process, to which the body was subjected to before death. Ignorance and misinterpretation of such postmortem artefacts leads to:...

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Decompositional Odor Analysis Database

ABSTRACT: This study, conducted at the University of Tennessee’s Anthropological Research Facility (ARF), describes the establishment of the Decompositional Odor Analysis (DOA) Database for the purpose of developing a man-portable, chemical sensor capable of detecting clandestine burial sites of human remains, thereby mimicking canine olfaction. This “living” database currently spans the first year and a half of burial, providing identification, chemical trends and semi-quantitation of chemicals liberated below, above and at the surface of graves 1.5 to 3.5 ft deep (0.45 to 1.0 m) for four individuals. Triple sorbent traps (TSTs) were used to collect air samples in the field and revealed eight major classes of chemicals containing 424 specific volatile compounds associated with burial decomposition. This research is the first step toward identification of an “odor signature” unique to human decomposition with projected ramifications on cadaver dog training procedures and in the development of field portable analytical instruments which can be used to locate human remains buried in shallow graves.

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Establishing Identity Using Cheiloscopy And Palatoscopy

Abstract Establishing a person's identity can be a very difficult process. Dental, fingerprint and DNA comparisons are probably the most common techniques used in this context, allowing fast and secure identification processes. However, since they cannot always be used, sometimes it is necessary to apply different and less known techniques. In this paper, the authors describe two unusual techniques: cheiloscopy and palatoscopy. It is known that due to their special features, both lip grooves and palatal rugae can be used successfully in human identification. This paper reviews the techniques of cheiloscopy and palatoscopy, and describes the different classifications and their advantages and limitations....

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