Module 3 - Arson and Explosives

Module 3 - Arson and Explosives

Arson is the crime of setting a fire for an unlawful or improper purpose. It is a problem because it costs hundreds of millions of dollars annually in increased insurance costs, increased taxes, loss of jobs, loss of business revenue, and treatment of injuries. Arson differs from other crimes in that it is not immediately obvious that a crime has occurred. It is a difficult crime to investigate because the fire frequently destroys evidence. Despite this, numerous telltale clues are often left behind an arson fire that can help investigators find the culprit.

Arson is a relatively easy crime to commit because a fire is easy to light. A small fire quickly becomes a big fire if it is not controlled early. Therefore, the amount of damage caused by an arsonist usually depends on the amount of time that lapses before firefighters arrive.

Explosions occur less frequently than arson fires. The likely reason for this is that, for the most part, creating an explosive device is more difficult than starting a fire, and starting a fire requires very little planning and effort. Law enforcement officers have several unique ways to investigate crimes involving an explosion.

Organization of the Module:

• Lesson 1 examines the nature of a combustion reaction and the motives and profile of an arsonist.
• Lesson 2 outlines the various methods used to investigate arson fires.
• Lesson 3 describes the various types of explosives and identifies some explosive detection techniques.
• Lesson 4 examines the details of two historical crimes that involve arson and explosives.

Module Learner Objectives

By the end of Module 3, you should be able to…

• identify the components necessary for a combustion reaction
• explain how combustion differs from an explosion
• understand the terminology that relates to arson (such as accelerant, blast, booster, detonation, endothermic, exothermic, fuel, ignition, pyrolysis, oxidizer)
• describe the three points and conditions of a fire: flash point, flammable range, and ignition range
• describe the level of oxygen needed to keep a fire burning and the various products of a combustion reaction that can cause a fire to continue
• describe arson and determine the various types of arson by the severity of the damage caused
• identify various motivations for arson and possible strategies to eliminate this crime
• recognize the steps in the investigative process of a possible arson
• identify various tools and methods used in arson investigations (such as portable arson sampler, chromatography, lasers, solid-phase microextraction, arson profiling, metal oxide sensors, canines, photoionization detectors)
• compare the numbers of human fatalities and human injuries caused by arson using graphed data
• compile and present various data related to arson (such as local statistics, common motives, profile of typical arsonist, child arsonists, total cost of arson investigations, arson prevention methods)
• identify the three basic components of an explosive device: fuel source, oxidizer, and ignition.
• identify and describe various types of explosive devices (including gunpowder, dynamite, nitroglycerin, saltpetre, guncotton, TNT, PETN, picric acid, plastic explosives)
• describe various devices or techniques used by forensic experts to detect explosives (such as robots, EGIS, canines, X-rays, metal detectors, ion mobility spectrometry, honeybees)
• recognize various types of explosives (such as explosive bombs, chemical bombs, inert bombs, nuclear bombs) and understand the function of each.
• explore a historical crime case(s) involving arson and/or explosives (such as Timothy McVeigh, Frederick Small, U.S. Embassy in Kenya, Pan Am Flight 103, 9/11 World Trade Center Disaster, Unibomber).