Crime & Clues

Arson Investigation

The Fire

Arson investigation starts with the fire itself. To create and sustain a fire three factors must be present. The three factors are known as the fire triangle (Peige ed.,1977). The fire triangle consists of oxygen, a fuel source, and heat. In most cases the percentage of oxygen concentration must be above 16% (Peige, ed.,1977). The fuel may be any flammable substance. The heat source needs only to match the ignition temperature of the fuel.

In a fire involving arson the arsonist will have tampered with one or more of the factors in the fire triangle. The arsonist may increase the fuel load by introducing flammable material or by adding accelerants such as kerosene, gasoline or alcohol (French, 1979) The arsonist may increase the oxygen content of a structure by opening windows or punching holes in ceilings and walls (French, 1979) Fire will follow the highest concentration of oxygen to its source. By ventilating a structure at the top and starting a fire at the bottom of the structure an arsonist can cause the fire to race upward through the structure. The fire will rapidly involve the whole structure rather than be confined to one room.

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The Role Of Entomology In Forensic Investigations

Prologue

This paper is intended for use by police and other emergency personnel who have occasion to be in contact to the recently and not so recently deceased. When first introduced I will mention the scientific name of the various species of insects which colonize bodies after death. After the first mention I will use the common name which is easier to both remember and pronounce.

All too often insect evidence is accidentally destroyed be emergency personnel who fail to realize the importance of this evidence. This author has personally witnessed well meaning emergency personnel shooing away insects and maggots at a scene. I have even observed emergency personnel stomping on maggots as they attempt to flee from the activity around the body. Education in the proper collection and preservation procedures is essential.

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Forensic Osteology Part One

What is Forensic Osteology? Well it is the child of Physical Anthropology (study of the human physique) and Pathology (study of the processes causing death). Its grandparents were Medicine and Anatomy. Its other relatives are Paleontology (study of ancient humans and related species) and Zoology (study of animals). Forensic Osteology is one of the newer disciplines in forensic investigations. This youngster may call on any of his/ her relatives for help and expertise during an investigation. At times Physical Anthropology and Pathology may argue about who is in charge but in the end they usually co-operate to get the job done. Not so long ago Criminology approached Osteology and said "Hey, I could use your help". Osteology gave itself the title of forensic osteology.

Technically speaking Osteology is the study of bones. Forensic osteology is the study of bones as they relate to a crime. Many sources will define this as Human Osteology, Physical Anthropology or Forensic Pathology according to the source. I agree in part with some authors that a pathologist''s experience in medical aspects and anatomy may be the best person for the job. However, few pathologist have experience in excavation of outdoor site were remains are located. As well, few Pathologists/medical examiners/coroners have extensive knowledge of the anatomy of animal remains. Even an experienced archeologist/anthropologist may seek a veterinarian or zoologist for further advice on remains which are hard to identify.

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Fingerprinting the Dead

Obtaining fingerprints for identification is a long established law enforcement practice. When the practice started, is was most common to use printers ink applied to the fingers which were then pressed onto paper cards. Later specialized inks were employed to improve the quality of the prints obtained. While ink is still used today, many agencies are now using computer "live-scan" methods to record reference prints.

One of the challenges in obtaining reference prints has always been how to obtain them from the deceased. Ink has often been used with success, but it can be difficult, especially with rigor stiffened or mummified fingers. Live-scan is not a practical option, at least not until someone develops a portable scanner.

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