Death Investigation - Section 2

Forensic anthopology

application of skeletal analysis and techniques in archeology to solving criminal cases

Forensic anthropologists:

• assist in the identification of deceased individuals whose remains are decomposed, burned, mutliated or otherwise unrecognizable

• use skeletal abnormalities to potentially determine the cause of death, past trauma such as broken bones, as well as diseases such as bone cancer

• testify in court as expert witnesses

From remains, anthropologists can determine if the bones are human

differences between human and animal bones:

• gross skeletal anatomy

• bone macrostructure

• bone microstructure - histology

Froms remains, anthropologists can determine an age range

skeletal characteristics that can determine an approxiamte age:

• teeth

• size and development of the skull

• skull sutures

• growth plates

• arthritis

• long bones

From remains, anthropologists can determine a person’s sex

using the pelvis:

• pubic arch

• sacrum

using the skull:

• chin shape

• jaw angle

• mastoid process

From remains, anthropologists can determine a person’s stature

• given as a range of possible values and typically computed by measuring the bones of the leg

• based on a series of formulas that have been developed over time by the examination of mulitple different skeletons

• sex, ancestry, and age shoul be determined before attempting to ascertain height, if possible

• if femur is not present, other bones can be used to esitmate stature - tibia, fibula, radius, ulna, humerus

Forensic facialn reconstruction

process of recreating the face of an individual from their skeletal remains

the skull can provide clues to personal appearance:

• brow ridge

• distance between the eye orbits

• shape of the nasal chamber

• shape and projection of the nasal bones

• chin’s form

• overall facial bone profile

Forensic odontolgy/forenisc dentistry

handling, examination and evaluation of dental evidence

• assists in identification of human remains

• assists in determining age

use of dental records including radiographs, ante-mortem and post-mortem photographs, and DNA

advantages and disadvantages

Bite mark comparison

• bite marks are unique like fingerprints

• left on either the victim, the perpetrator, or an object found at the crime scene

• usually seen in cases of sexual assault, murder, and child abuse

• can be found anywhere on a body, particulalry on soft or fleshy tissue

comparison:

• photographs, molds

• compares dental arch size and shape, tooth position, individual detnal characteristics

controversy:

• bite mark comparison isn’t used very often

• many wrongful convictions

• not very accurate in some cases

• never used as sole evidence

Forensic entomology

the use of the insects and their arthropod relatives that inhabit decomposing remains in death investigators

used to estimate post-mortem interval, changes in body position, cause of death

determined by:

• type of insects present

• development of insects

Factors affecting insect activity

• temperature

• moisture level

• sun exposure

• air exposure

• geography

• weather

Insect presence timeline

1. Fresh stage - blowflies

2. bloat stage - true flies, ants

3. active decay stage - scavenger flies

4. advanced decay stage - skin bettles

5. dry decay stage - centipedes, milipedes, isopod, snails, and cockroaches

Forensic fingerprint examination

comparison of post-mortem fingerprints to known fingerprints in the state or federal system for identification purposes

• an antemortem record of fingerprints must exist

• postmortem fingerpints are collected during autopsy

• typically, known prints come from incarceration or government employment

• usually performed by specialists with the BCI identification unit

Forensic toxicology

the analysis of biological samples for the presence of toxins, includings drugs and quantitation

• sample fluids collected: blood, urine, vitreous fluid, gastric contents

• used in various cases - illicit drug overdoses, prescription pill overdoses, poisoning, drunk-driving

• basic panel vs extended panel

• results of toxicology testing are then interpreted in conjuction with history, scene investigation, and autopsy to determine cause and manner of death

Forensic toxicologist examine physical evidence submitted to the lab for the presence of illegal substances

items collected from the scene for examination:

• unknown powders/pills/fluids

• pipes

• spoons

• syringes

• bindles

determination of presene through:

• gas-chromatography mass spectrometry

• infrared spectroscopy

Forensic pathology

pathology that focuses on determining the cause of death examining a corpse

duties of forensic pathologists:

• perform post-mortem examination (autopsy or external)

• collect and examine tissue specimens under the microscope (histology)

• collect and interpret toxicological specimens of body

• determine the cause of death

• create autopsy reports

• testify in court as an expert witness