 |  Criminal Investigation, 8/e Charles R. Swanson,
University of Georgia
Neil C. Chamelin,
Assistant State Attorney, Second Judicial Circuit
Leonard Territo,
University of South Florida- Tampa
Arson and Explosives Investigations
Chapter OutlineI. PRELIMINARY INVESTIGATION (See Slide 18-2) A. One effective way to determine fire causes is to determine the point of origin. B. After the area of origin has been established, the investigator should check for the level of origin by examining the bottoms of shelves, ledges, moldings, and furniture and all sides of the legs, arms, and framework of reconstructed furniture. C. The floor and lower areas of the room produce the most clues to the cause fo the fire, because they are living area. II. WHERE AND HOW DID THE FIRE START? (See Slides 18-3, 18-4, 18-5, and
18-6) A. Two Factors Needed to Cause Fire During the investigation, it should be borne in mind that a fire always has two causes: a source of heat and material ignited. B. Accidental Fires Once the point of origin has been discovered the next step is to determine how the fire started. Even though arson may be suspected, the investigator must first investigate and rule out all possible accidental or natural causes. C. Spontaneous Heating and Ignition There are a few fundamental causes of spontaneous heating, but the conditions under which these factors may operate are numerous. III. BURN INDICATORS (See Slides 18-7, 18-8, 18-9, and 18-10) A. Burn indicators are the effects of heat or partial burning that indicate a fire’s rate of development, points of origin, temperature, duration, and time of occurrence and the presence of flammable liquids. B. Interpretation of burn indicators is the principle means for determining the cause of a fire, especially arson. IV. FIRE SETTING AND RELATED MECHANISMS (See Slides 18-11, 18-12, 18-13,
and 18-14) A. Ignition Devices 1. Matches. Only juvenile arsonists and pyromaniacs seem to favor striking matches. 2. Gasoline. Gasoline and other accelerants are very popular with many different types of arsonists. 3. Chemicals. Various chemical combustions have been used to set fires. 4. Gas. Although not commonly encountered, the combination of gas and the pilot light on the kitchen stoves of many residences is always a possibility. 5. Electrical Systems. Any wiring system, including doorbell and telephone circuits, can be used as a fire-setting tool. 6. Mechanical Devices. Alarm clocks were once a favored weapon of arsonists. B. Plants A plant is the material placed around the ignition device to feed the flame. C. Trailers Trailers are used to spread the fire. D. Missing Items Sometimes items that are missing from the fire scene can prove valuable. V. ARSON FOR PROFIT Understanding the motive of the arsonist is extremely important if the investigation is to be successful (See Slides 18-15 and 18-16). A. Financial Stress as the Primary Cause The homeowner or business owner who decides to arrange an arson fraud may do so out of submission to financial stress. 1. Short-Term Business Problem a. Desire to relocate or remodel b. Buildup of slow-moving inventory c. Outmoded technology 2. Satisfaction of a Legal or Illegal Debt. The businessperson or homeowner whose property is destroyed by fire does not always broadcast clear signals of financial stress. B. Purely Fraud Schemes as the Primary Motive These types of arson-fraud schemes result from the planning and plotting of professional fraud schemers and their associates. 1. Redevelopment. In cases where a defined tract has been designated for the receipt of federal redevelopment funds, owners and investors may stand to make more money if existing buildings on the tract are razed at no cost to themselves. 2. Building Rehabilitation. In order to improve the condition of old or rundown dwellings, a variety of federal and state loan and loan insurance programs are available for housing rehabilitation. 3. Real Estate Schemes. In many core urban areas, the most common form of arson for profit involves the destruction of dilapidated multifamily housing. 4. Planned Bankruptcy. Although this variation of arson for profit is not encountered often, its incidence does seem to be growing. C. Arson Generated by Third Parties This is another broad category of arson for profit, where the beneficiary of the fire is not the owner-insured but a third party who arranges for the fire out of some economic motive. 1. Elimination of Business Competition. This type of scheme is motivated by someone who seeks to create a business monopoly or at least to maintain a competitive edge. 2. Extraction of Extortion Payments. Offenders who demand extortion payments to let someone remain in business will necessarily identify themselves. 3. Labor-Management Grievances. Arsons in business establishments may be the result of an unresolved labor-management grievance for which the perpetrator felt there was insufficient redress or resolution. D. People and Paper Evidence in Arson-for-Profit Investigations The presence of certain documents is a good, direct indicator of fraud, economic stress, or a combined fraud-stress motive. VI. OTHER MOTIVES FOR ARSON A. Revenge, Spite, Jealousy This category includes jilted lovers, feuding neighbors, disgruntled employees, quarreling spouses, people getting even after being cheated or abused, and people motivated by racial or religious hostility. B. Vandalism, Malicious Mischief Vandals set fires for excitement and have no other motive. C. Crime Concealment, Diversionary Tactics Criminals sometimes set fires to obliterate the evidence of burglaries, larcenies, and murders. D. Psychiatric Afflictions—the Pyromaniac and Schizophrenic Fire Setter Pyromaniacs differ characteristically from other arsonists in that they lack conscious motivation for their fire setting. E. Vanity, Hero Fires On occasion the person who "discovers" a fire turns out to be the one who started it and did so to be a hero. F. The Female Fire Setter The female arsonist usually burns her own property, rarely that of an employer or neighbor. G. The Child Fire Setter Authorities on fire-setting behavior believe that repetitive or chronic fire setting by children represents a severe behavioral symptom or psychological disturbance. H. The Adolescent Fire Setter One study of adolescent male fire setters showed that home-centered fire setting diminished as the age of the fire setter increased. VII. DETECTION AND RECOVERY OF FIRE-ACCELERANT RESIDUES Because flammable liquids flow to the lowest level, heat travels from this level up, and the charring on the bottom of the furniture, ledges, and shelves will be as deep as, or deeper than, the charring on the top. VIII. SCIENTIFIC METHODS IN ARSON INVESTIGATION (See Slides 18-17 and
18-18) A. Detection of Fire Accelerants Several types of portable equipment are available to the arson investigator for detecting residues of flammable liquids at fire scenes. 1. Olfactory Detection. The sensitivity of the human nose to gasoline vapor is about 1 part per 10 million. 2. Chemical Color Test Detectors. Chemical color tests may be used to detect both liquid accelerant residues and their vapors. 3. Catalytic Combustion Detectors. The most common flammable vapor detector operates on the catalytic combustion principle and is popular known as a sniffer, combustible-gas indicator, explosimeter, or vapor detector. 4. Flame Ionization Detector. In the flame ionization detector the sample gas is mixed with hydrogen and the mixture is burned. 5. Gas Liquid Chromatograph. The portable gas liquid chromatograph (GLC) adapted fro field use, sometimes called the arson chromatography, is one of the most common detectors in arson investigations. 6. Infrared Spectrophotomer. Infrared spectophotometers can achieve high specificity to flammable liquids and high sensitivity (on the order of hundredths of a part per million). 7. Ultraviolet Fluorescence. This procedure consists of illuminating the darkened fire scene with an ultraviolet lamp. VIII. INTERVIEWS (see Slide 18-19) A. Possible Witnesses Prospective witnesses include tenants, businesspeople and customers fro the burnt building and surrounding buildings as well as passers-by, including bus drivers, taxi drivers, delivery people, garbage collectors, police patrols, and people waiting for busses and taxis. 1. Questions to Ask. Did you observe the fire? At what time did you first observe the fire? are examples of questions asked in an interview. B. Firefighters at the Scene Firefighters can be an invaluable source of information to arson investigators because of their technical knowledge and because of what they observe at a fire. 1. Questions to Ask. What time was the alarm receive? What time did you arrive at the scene of the fire? are examples of questions to ask firefighters. C. Insurance Personnel Three people may be interviewed to determine if the profit centers around an insurance claim: the insurance agent or broker, the insurance adjuster, and the insurance investigator. 1. Question to Ask the Agent or Broker. Who is the insured? Is there more than one person insured? Is the insured the beneficiary? 2. Question to Ask the Insurance Claims Adjuster. Did you take a sworn statement from the insured? Did the insured submit documents regarding proof of loss, value of contents, bills of lading, value of building, and the like. 3. Question to Ask the Insurance Investigator. Were you able to determine the cause of the fire? did you collect any evidence? D. Other Witnesses Concerning Finances of the Insured A number of other people may have information on the finances of the owner, including business associates, creditors, and competitors. 1. Question to Ask. How long have you known the owner/insured? What is the nature of your relationship with the owner/insured? E. News Media Personnel Individuals affiliated with these groups may have noticed something of value to the investigator or perhaps have films of the fire and fire scene. F. The Medical Examiner The autopsy should reveal whether any victim found dead in the fire was dead or alive before the fire started and what the cause of death was. G. Interviewing a Suspect The questions below are based on the assumption that the person to be interviewed is involved in arson for profit. 1. Questions to Ask the Suspect. Are you willing to cooperate in this investigation? How many other people are involved int eh arson-for-profit scheme? 2. Questions to Ask the Suspect, Specifically. What method was used to accomplish the arson? H. Interviewing the Target and the Owner The target of the investigation may be an owner, landlord, fire broker, or the like. 1. Questions to Ask the Target. Tell me in your own words what you know about this fire. When did you first hear of the arson? 2. Questions to Ask the Owner. Tell me in your own words what you know about this fire. How long have you owned the burned property? I. Interviewing a Potential Informant Who Is Not a Suspect Before interviewing a potential informant who is not a suspect, investigative efforts should be made to determine if the informant has any police record and, if so, if it could have any bearing on the reliability of the information provided. X. THE ARSON SUSPECT (See Slide 18-20) A. In some arson investigations, a single prime suspect may emerge and investigative efforts will be focused accordingly. 1. However, in most cases, a number of suspects emerge, and merely establishing that one or more of them had a motive to set the fire is not proof enough for an arrest and conviction. B. In probing an arson fire, seldom does direct evidence link a suspect with a fire. X. PHOTOGRAPHING THE ARSON SCENE A. Still Photography Photographing a fire scene can be a challenge. Adverse conditions—poor lighting, time constraints, inconvenient angles, and so forth—necessitate the use of camera equipment that is reliable and quick because there rarely is time to adjust the focus on every shot or arrange perfect lighting. B. Videotape While the average fire investigation does not require videotaping, it should be done if the investigator reasonably believes that the case will involve litigation. XI. EXPLOSIVES INVESTIGATION (See Slides 18-21, 18-22, and 18-23) A. Types of Explosions There are two major types of explosions: mechanical and chemical. 1. In mechanical explosions the high-pressure gas is produced by purely physical reactions. 2. In chemical explosions the generation of high-pressure gas is the result of reactions in which the fundamental chemical nature of the fuel is changed. B. Investigating the Explosion Scene The objects of the explosion scene investigation are no different from those for a regular fire investigation: to determine the origin, identify the fuel and ignition sources, determine the cause, and establish the responsibility for the incident. 1. Proper Tools and Equipment. Having the proper tools and equipment is essential in emergency situations such as explosion or bombing scenes, although equipment and tool needs are, for the most part, determined by the actual scene. C. Locating and Identifying Articles of Evidence Investigators should locate, identify, note, log, photograph, and map any of the many and varied articles of physical evidence. D. Analyzing the Fuel Source Once the origin, or epicenter, of the explosion has been identified, the investigator should determine what type of fuel was employed. This is done by comparing the nature and type of damage to the known available fuels at the scene. XI. BOMB THREATS (see Slide 18-24) A. Responding to Threats 1. Telephone Call. When a telephone bomb threat is made, the caller should be kept on the line as long as possible. 2. Evacuation. The decision to evacuate the premises should be made by the responsible party at the scene. 3. Industrial Plants, Shopping Centers, and the Like. When a bomb threat is reported at an industrial plant, office building, shopping center, or apartment complex, the assigned officer should contact the owner or manager of the scene and advise the responsible party that search procedures, evacuations, and so forth, are the responsibility of the building owner or person in charge. 4. Private Homes and Small Businesses. It is necessary to search a private home or small business and there are no responsible persons present to do a search, officers should conduct the search themselves. 5. Police and Public Safety Buildings. If a bomb threat is received against a police or public safety buildings by a civilian employee, the employee should refer the threats to a sworn officer and the chief of police should be notified. B. Searching for Concealed Explosives To help detect anything suspicious or out of the ordinary, search procedures should include interviews with persons familiar with the buildings or structures to be searched. C. What Not to Do A partial list of steps that should not be taken in the event of a bomb threat include: 1. Do not ignore bomb threats. 2. Do not touch suspected explosives. 3. Do not touch suspected bombs. D. Potential Concealment Areas for Bombs Areas of concealment for a bomb could include: elevator wells and shafts, including nooks, closets, storage rooms, false panels, walk areas, counterweights, motors, cables, and trash in shaft. XIII. SUSPICIOUS PACKAGES AND LETTERS A. The following are two examples of precautions that should be followed when encountering a suspicious package or letter: 1. If delivered by carrier, inspect for lumps, bulges, or protrusions, without applying pressure. 2. If delivered by carrier, balance-check to determine if it is lopsided or heavy-sided. |
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2002 McGraw-Hill Higher Education