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Arson Investigation Basics

excerpted from "Motive, Means, and Opportunity, A Guide to Fire Investigation."
American Re-Insurance Company, Claims Division, 1996.

Table of Contents

The Investigation

An arson investigation basically focuses on four areas:

1. Proof of incendiarism - comes from an examination of the fire scene by a qualified cause and origin expert.

2. Proof of opportunity - focuses on the security of the building when the fire was discovered and who had access.

3. Proof of motive - focuses on the insured's financial condition, profit or loss from operations and cash flow.

4. Miscellaneous connecting evidence - includes an examination of the insured's insurance history, operability of fire and burglar detection systems, how insured learned about the fire, etc.

A Checklist of Arson Investigative Procedures*

Here's a rundown of some of the procedures of an arson investigation:

1. Identify initial caller from fire/police tape or through interviews (911)

2. Obtain aerial photos/diagram of scene

3. Obtain insurance information

  • Identify public/private adjusters and insurance investigators

4. Perform background checks

  • Owner
  • Occupant
  • Victim
  • Caller

5. Record checks of the property involved

  • Title search
  • Assessor's record
  • Tax records, etc.

6. Weather conditions

7. Previous police activity and vandalism in the area

8. Police/fire reports

9. Laboratory reports

10. Check area hospitals

11. Check area gas stations

12. Financial information

  • Bank records
  • Personal records
  • Business records

13. Check newspaper/TV photos and articles

14. Request all information from insurance company

  • Policies
  • Amounts
  • Proof of loss
  • Taped interviews, etc.
  • All previous claims
  • Interview person who receives report of loss (agent/secretary)

15. Attempt to establish motive

Additional Procedures for the Fatal Fire

1. Medical Examiner called to the scene

2. Autopsy and x-rays of body taken

3. Description of condition of body at the scene noted

4. Check for pugilistic position of body

5. Take samples of area around the body

*This section is based upon and contains excerpts and quotes from "Basic Tools and Resources for the Arson Investigators: A Handbook," by the Federal Emergency Management Agency and the United States Fire Administration.

A. Legal Entry and Evidence Collecting


IMPORTANT!!! Legal entry and handling of evidence at a fire scene is absolutely critical. If a scene is not entered and evidence collected with the proper procedures, the evidence may not be admissible in court.

Investigators must decide both what to collect and where to collect evidence. Evidence that is insufficient or sampled from the wrong location can severely damage an investigation and a case against an arsonist. And, if evidence isn't collected at the scene, returning to the scene is problematic: evidence may be destroyed, diluted or altered.

Two major factors affecting admissibility in court of exhibits are:

  • The exhibit must be labeled so it's clearly and distinctly recognized in the lab or court as a specific piece of material recovered at the fire scene.
  • The exhibit must be uncontaminated or unaltered: in the same state it was in when it was collected.

To improve the chances of admissibility, evidence should be:

  • Clearly identified with a proper label, tag or mark
  • Correctly collected and placed in appropriate containers
  • Stored and handled securely with a short, documented chain of custody and if possible all evidence should be handled by one person

1. Comply with legal requirements--

a. Fire officials normally need no warrant to remain in a building for a reasonable period of time to investigate the cause of a fire after it has been put out.

b. When in doubt, arrange an administrative or criminal search warrant for all searches by calling the prosecutor's office.

c. Contact the district attorney, crime lab specialists, or other legal experts any time questions come up about handling the scene or evidence.

2. When a search warrant is needed, it must be specific and should include--

a. The address and description of the property to be searched

b. Specific items being searched for

3. When there's reason to believe that evidence will be located where the search is to take place, you may have probable cause. A Probable Cause Affidavit may have to be written and it should include--

a. information about where, when, and what occurred

b. information in chronological order that leads to the conclusion that evidence will be discovered in a particular location

4. When other investigators need to examine the scene, the following applies--

a. For maximum effectiveness, it must be a cooperative effort of all parties.

b. Investigators must preserve suspected fire causes for later examination and analysis.

c. Arson immunity laws permit information sharing between fire and police investigators and insurance company investigators.

(1) Arson immunity statute

(a) The major purpose is to increase the flow of vital investigative information between insurance companies and law enforcement agencies. It allows insurers to inform the state fire marshal or other such persons of fires that appear to be suspicious in origin and permits insurers and arson investigators to exchange information developed during their separate investigations.

(b) Allows authorized agencies (state and federal fire marshals, law enforcement officers, insurance commissioners and prosecuting attorneys) to require that insurance companies release all information concerning a policyholder involved in a fire loss including history of premium payments and previous claims, as well as other files.

(c) Requires insurers to notify authorized agencies of suspicious fire losses

(d) Grants limited civil and criminal immunity to those insurers providing information under the provisions of the statute

(e) Provides for the exchange of information between insurers and authorized agencies, and the exchange of information among authorized agencies

(f) Provides for confidentiality of released information


5. Items in plain view during a legal entry by an investigator may be seized. But NOTE--

a. Items discovered during fire suppression are fair game.

b. Items discovered during salvage and overhaul are fair game.

6. The fire investigation at the scene must be performed at or near the time of the fire. An exception may be when the investigation of a fire that occurred at night halts and recommences in the morning because--

a. There is more light.

b. There is more equipment.

c. There is more assistance.

d. Conditions are better.

e. Hazards to fire fighters have been removed.

7. Investigators should document any investigator fatigue or discomfort due to--

a. length of time on scene

b. weather

c. common sense controls

8. When the property is released to the property owner--

a. There should be a "ceremony" or formal acknowledgment of giving control back to the owner or his representative.

b. The release of the property back to the owner or representative should be documented so that there's no question about when it occurred.

c. After the property is released to the owner, it can only be re-entered with consent or a warrant.

B. Preliminary Scene Examination*

1. Here is a summary of tasks to be completed at the fire scene:

a. Remove all debris not germane to the fire cause.

b. Cleanse all tools before bringing them into the area of origin (AO) and establish an evidence collection area, where tools and evidence containers should be assembled.

c. Replace furniture, appliances and other materials to their pre-fire positions using the maps drawn by the occupants.

d. Analyze fire flow patterns, damage patterns and evidence like shields and shadows, beveling, inverted cone burn patterns, etc. Document evidence with photos, diagrams and notes.

e. Examine and document each potential accidental ignition source in the AO. Do this even if there is gross evidence of arson.

f. Diagram the room of origin with accurate shape, dimensions, windows, doors and other key features plus locations of key items and areas of evidence. Record ceiling com-position and wall and floor surfaces on the diagram. Measure movable items of evidence with a tape from fixed locations. With tape measure, diagram and measure building exterior. Show first floor and basement entrance/exit points with lock types and conditions. Orient all drawings to north with a magnetic compass.

g. Document and collect physical evidence using appropriate methods.

h. Call in experts for advice if required (electrical inspectors, furnace technicians, etc.)

i. Contact arson prosecutor before releasing the scene to see if he/she would like to tour it with the investigation team.

2. Initial procedures for fire investigators at the scene include--

a. Check for possible secondary incendiary devices

b. Check license plates of automobiles in the area of the fire

c. Ensure that access to the scene is under control

Access to the fire scene must be controlled to avoid scene contamination and injuries. Law enforcement agencies usually handle site access.

In small residential or building fires, investigators work from the outside to the inside of the building. In large fires or explosions a search strategy must be devised and followed by investigators.

3. At the scene, investigators should note--

a. activities in the area before and after the fire started

b. location of all electrical and heating equipment

c. smoke and heat patterns and structural damages (including any fire "V" patterns)

d. dimensions, type of construction and furnishings

e. depth of char on items

4. Secure the area--

Don't rush to give up the scene. Take your time with each of these steps.

a. Defer overhaul of the scene until a thorough examination of the scene is completed.

b. Secure and seal off the area with police barriers, ropes, etc.

c. Restrict entrance to the scene - including officers, other investigators and news media. (Anyone entering the scene should be prepared to offer court testimony about his or her reasons for entering.)

d. Arrange for a patrol of the area while the investigation is pending.

e. Searches and seizures must be lawful, administrative (based on statute) or with warrant based on probable cause. f. Generally the property owner or occupant's consent is required to search the scene if the fire scene has been released by the fire department or time has elapsed since the fire.

5. When the fire occurs in transient areas and inner cities, special guidelines apply-*

Always obtain expanded personal identification (name, present address, date of birth, social security number, work place or social worker, work and home phone numbers, next-of-kin and their addresses, etc.). This gives the investigator who must locate a witness months or years later multiple avenues to pursue.

6. For chaotic street scenes, it's important to interview these people first.

a. Search the crowd near the fire for persons who: appear distressed, try to leave when you approach or meet and hold your eyes when you approach.

b. Interview people living or working in adjacent buildings as early as possible

c. Obtain expanded personal identification information

*Sections B and C are excerpted from a compilation of material from sources listed in the bibliography at the end of this chapter.

C. Obligations and Responsibilities

1. Fire Fighters

There has always been a special relationship between fire fighters and arson investigators. In fact, very often arson investigators come from the ranks of fire fighters. Of course, the first responsibility of a fire fighter arriving at the scene of a burning building is to save the lives of anyone who might be in danger. Their second responsibility is to put out the fire. But their third responsibility is to be observant and not unnecessarily disturb the fire scene. As the first responding personnel, fire fighters are in the best position to observe and report any suspicious circumstances.

Here's a check list for first-responding fire fighters to keep in mind:

a. Weather conditions during response

b. Traffic conditions during response

c. View (perspective of building on arrival)

d. Extent of fire/smoke on arrival

e. Rapidity of fire/smoke spread on arrival

f. Color of flames and smoke on arrival

g. Explosion - if any

h. Suspicious persons at scene or leaving on arrival

i. Condition of fire hydrants on arrival

j. Access to the fire building

k. Building security at time of arrival (doors/windows)

l. Was view into structure blocked?

m. Were contents as they should have been?

(1) Personal items present

(2) Food in cabinets - refrigerator

(3) Cooking/eating utensils

(4) Power/gas on

n. Equipment or possessions removed

o. Odors at point of origin

p. Multiple fires

q. Did fire flash when water was introduced?

r. Holes in walls or ceilings

s. Evidence of extreme heat

t. Obstructions in building hampering fire fighting efforts

u. Was sprinkler system tampered with?

v. Was alarm system tampered with?

w. Methods used prior to fire department arrival to extinguish fire

x. Methods used by fire department to extinguish fire

y. Time that fire was declared as extinguished

z. Any idea of cause?

aa. Were owner/occupants at the scene? (How were they dressed? How did they act?)

bb. "Eager Beaver" at scene

cc. Same people at many fires

dd. Remember and record what you did

2. Fire Investigator

Here are some tasks and guidelines for investigators:

a. Respond to serious fires or possible arson fires immediately after fire apparatus is dispatched with complete "ready-to-go" gear, tools and evidence collection equipment.

b. First investigator on the scene must call for additional assistance, if needed, from the Fire Prevention Unit, State Fire Marshal's Office or municipal police.

c. Speak to the fire officer-in-charge and the first-in firefighter for their initial appraisal of the situation.

d. Immediately upon arrival, survey the exterior and interior of the structure (if safe entry can be made!), the goals being to:

(1) Assess probable fire origins

(2) Secure obvious evidence

(3) Control fire overhaul procedures to protect evidence

e. If fire fighters are still working to extinguish the fire when you arrive, making it impossible for you to conduct a scene examination, begin interviewing witnesses. Record witness' statements in writing and have them sign their statements. (See next section.)

3. Crime Scene Team Leader

Here are some guidelines for the team leader on the scene:

a. Attempt to reconstruct what happened to determine probable sources of evidence.

b. Take notes answering the questions Who? What? When? Where? Why? How? Use a tape recorder if possible. Record:

(1) Date

(2) Time

(3) Weather conditions

(4) Who is present

(5) Lights in structure on or off

(6) Doors locked or open

(7) Air conditioner in structure on or off, etc.

c. Assign responsibilities to team members: evidence collection, photographs, fingerprints, etc.

d. Notify agencies

(1) Notify appropriate persons in the departmental chain of command.

(2) Notify the prosecutor's office, medical examiner or coroner and other specialists who may be required, in accordance with departmental guidelines.

(3) Notify forensic science lab for response and technical assistance (if required).

e. Relate the evidence to the fire scene

(1) Plan evidence collection

(2) Identify the nature of the item, if possible

(3) Photograph the item before touching or moving it

(4) Record evidence in field notes/sketches (include measurements)

(5) Identify witnesses present during discovery

4. Investigator Safety

Building collapse, asbestos dust, sharp nails, and poisons are a few of the hazards an investigator faces. The following steps will help to ensure investigator safety at the site:

a. If possible never work alone. But if you must, be certain a responsible individual knows your location and timetable.

b. Know the signs of structural fatigue and failure caused by a fire.

c. Always wear a helmet, boots, goggles, and other protective gear at the scene. d. Interview owner/occupants about storage of any poisonous substances.

e. Wear an air filter mask.

f. Delay excavation until heavy smoldering ends.

g. Allow fresh air to circulate to dissipate carbon monoxide and other gases.

h. Delay excavation to allow drainage and encourage rusting of metal surfaces. (Burn patterns on metallic surfaces become more apparent when they rust.)

D. Interviews*

Begin interviewing witnesses as soon as possible. Information gathering should be aimed at uncovering information about these critical areas:

  • Information about events leading to the first appearance of fire.
  • Where the fire first appeared and its symptoms.
  • People present when fire occurred.
  • Possible accidental causes.
  • Map of contents and layout of the area of origin before the fire.
  • Details of possible motives for a given person to set the fire.
  • Legal releases and comprehensive statement from owner/occupant.

1. Who to interview-

a. Fire fighters

b. Patrol officers

c. Owners

d. Occupants

e. Discoverer of fire

f. Witnesses

What to do-

  • Park your response vehicle as close as safely possible facing the fire scene.
  • Locate building occupants, passersby, eye-witnesses or those living or working in abutting buildings.
  • Take written or taped statements, privately, one witness at a time out of ear shot of other witnesses.
  • Try to have witnesses physically point out their observations about the building and surrounding areas.
  • Have witnesses sign their statements.

Essentials for interviewing-

  • Obtain full data about witness - name, address, age, phone number, etc.
  • Record where the witness, property owner or victim was at the time of the fire.
  • Obtain the facts: what did the person see?
  • Verify witness' statement. (Is what they said possible?)
  • Leave the way open at the conclusion of the interview to contact the witness' again if further information is needed.
  • Never conduct interviews in front of other witnesses.
  • Do not make critical or negative comments to influence the witness' attitude toward the investigation. Remain neutral and interested in what the witness has to say.
  • With a hostile witness, establish an informal rapport before asking anything about the fire.
  • Never discuss controversial subjects unrelated to the fire (for instance, politics).
  • Handle the property owner or victim of a fire with great care, particularly if he/she is a suspect.
  • Do NOT suggest in any way that you know anything about the cause and origin of the fire.
  • If possible, bring an associate with you to interviews to protect your integrity and pro-vide a source to corroborate witness' statements: however, this person is in addition to, NOT instead of, written or recorded notes. The accompanying associate can corrobo-rate an uncooperative witness' oral statement if necessary.
  • Ask cooperative witnesses to provide substantial detail about everything they know about the fire.

2. What to ask-

a.Fire fighters at the Scene:

(1) Who reported the fire?

(a) How was the fire reported?

(b) When was the fire reported?

(c) Where was it reported from?

(d) To whom was it reported?

(2) What time was the first alarm received?

(a) How was the alarm received?

(b) What was the time of arrival?

(3) Who discovered the fire?

(a) How was it discovered?

(b) When was it discovered?

(4) Identify the first fire fighters or units at the scene.

(a) Did the fire fighters encounter any suspicious activity en route to/or at the scene?

(b) How much time elapsed from the discovery of the fire to the time of the alarm and arrival at the scene?

(5) Describe the accessibility to the scene.

(a) General condition of the fire:

1) extent of fire (intensity)

2) location of fire(s)

3) did anyone meet fire fighters upon arrival?

4) any familiar spectators at the scene?

(b) Color of smoke or flame?

1) unusual considering the fire load?

2) where were fire and smoke coming from?

3) what was the rapidity and spread of the fire?

(6) How was entry gained into structure?

(a) Describe condition of doors and windows.

(b) If entry was forced - how and by whom?

(7) Upon entry - where was fire centered? Were there separate fires?

(8) Any unusual odors?

(a) Where were odors coming from?

(b) When were odors noticed?

(9) Was the fire unusually difficult to extinguish? (Did the fire flash when water was introduced?)

(10) Were there any obstructions to fire-fighting operations? Example: hydrant cap missing, sprinkler tampered with

(11) Was the alarm system functioning properly?

(12) Did any witness make statements to fire fighters?

(13) Was owner at scene?

(a) Was owner available when contacted?

(b) What was owner's attitude?

(c) What was the owner's opinion as to cause?

(14) Names of persons allowed into scene.

(15) Was any physical evidence taken from scene?

(16) Were any photos taken of fire in progress?

(17) Any holes in walls or ceilings?

(18) Opinion as to how fire started?

(19) Name - Address - Phone (Day/Night).

b. Person(s) Discovering the Fire:

(1) What time was the fire discovered?

(2) What was seen, heard, smelled?

(a) Color of smoke/flames?

(b) Was an explosion heard?

1) Did it sound like thunder?

2) Did it sound like the crack of a whip?

(3) What made you notice the fire?

(4) Rapidity and spread of fire?

(5) Was building secure upon discovery of fire?

(6) Other persons at the scene?

(7) Vehicles at/leaving scene?

(8) Weather conditions?

(9) Name, address, phone, date of birth.

(10) Preserve tape-recorded emergency calls to fire/police.

(11) Where were you when you first observed fire?

c. Witnesses/Neighbors:

(1) What time did you notice the fire?

(2) Where was the fire first located?

(3)Rapidity and spread of fire?

(4) What did you see/hear/smell?

(a) Did you hear an explosion?

(b) Color of smoke/flame?

(5) Any activity around the scene before/after fire?

(a) Anyone seen leaving before/during the fire?

(b) Were owners/occupants at the scene?

(6) Vehicles? (Did any vehicles leave the scene?)

(7) General information concerning owner/occupants:

(a) Previous residences or other properties owned

(b) Marital status

(c) Employment of owner/occupant/insured

(d) Financial problems of subjects

(e) Unusual activity

(8) Opinion as to how fire started?

(9) Prior fires or vandalism in the neighborhood?

(10) Name, address, phone, date of birth

(11) Did you observe anyone removing contents before the fire?

(12) Where were you when you first observed the fire?

d. Owner/Occupant:

(1) Date and time of fire?

(2) Who discovered the fire?

(3) How were you notified of the fire?

(a) Who notified you?

(b) When notified?

(c) Where were you when notified?

(d) Alibi?

(4) Who was the last person in the building?

(5) Who has keys to building?

(6) Unusual activity before fire?

(7) Was building/property for sale?

(8) Neighborhood/zoning problems?

(9) Type of business (if applicable):

(a) Who are employees?

(b) Who is accountant?/Where are financial records?

(c) Banks?

(d) Who are customers/suppliers?

(e) Description and location of business records?

(10) Owner or tenant?

(a) How long?

(b) Leases?

(11) Insurance Policies

(a) Agent/Public Adjuster?

(b) Insurance companies?

(c) Description of policies?

1) Type and number

2) Amount of coverage

(d) Any recent changes in amount of coverage?

(e) Any previous losses?

(12) Description of contents of building/store/apartment -

(a) Location of flammables, utilities, etc.?

(b) Age of building?

(c) Sprinklers/alarms?

(d) Floor plan?

(e) Fire hazards/flammable liquid storage?

(f) Description of utilities?

(g) Description of appliances?

(h) Alterations/repairs?

*This section is based upon, and contains excerpts and quotes from "A New Approach to Fire and Arson Investigation" by Detective Lt. Robert A. Corry, Unit Commander, State Fire Marshal's Office, Boston, MA and Brett Vottero, Arson Prosecutor, Hampden County District Attorney's Office, Springfield, MA. It is used with their permission.

Reprinted with permission.

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