The role of evidence and the scientific method in arson investigation

Arson is a fire purposely set fire. By definition, therefore, such fires are not accidental and it becomes the responsibility of the arson investigator to become aware of the various causes of arson in an attempt to assist the possible criminal investigation that may result from the act of arson. In doing so, the arson investigator must be diligent to preserve any possible evidence that may be beneficial in the determining how, when, who, and what may started the fire. In any arson investigation, extreme care must be taken until such time as arson is either confirmed or eliminated as a possible cause of the fire.

In any given calendar year approximately 500,000 fires occur every year in the United States (Technical Working Group on Fire/Arson Scene Investigation, 2000). Objectivity is an essential element of every fire investigation and the findings of the investigation must be based on sound and supportable evidence. Physical evidence is the arson investigator's best method of proof due to its inherent reliability and objectivity. Unfortunately, physical evidence from a fire scene is often difficult to interpret and pinpointing any human involvement in the arson procedure is even more difficult.

II. General Discussion

There is a general feeling among prosecutors and the arson investigators who assist the prosecutor in litigating arson cases the such cases are largely circumstantial and, therefore, difficult to win. Until very recently, there was very little scientific support for how and why fires started and there was also a generalized bias against arson cases because some legal experts, judges included, viewed the cases as being more properly classified as civil matters as opposed to criminal. Improvements in technology and a corresponding increase in the level of professionalism among arson investigators have served to alleviate both matters as a source of concern. In today's society, the arson investigator is no longer the fireman on the force who can no longer function in the field fighting fires but is not ready for full retirement. For too long this was the case and fires were never fully investigated. Now, most large cities employ professionally trained arson investigators and, in the courts, there is wider acceptability of arson investigators as expert witnesses. Additionally, arson is now, due to the social cost and potential danger involved, considered a legitimate and serious crime.

Cooperation between the arson investigation team and the prosecutor is essential if a conviction is to be obtained (Federal Emergency Management Agency, 1994). Each brings his or her own expertise and experience to the investigation and subsequent prosecution and both professional groups should afford the other due respect.

III. Scientific Method

Arson investigation has been performed by investigators for hundreds of years and done successfully relying entirely upon common experience and accumulated knowledge but the advent of modern technology has caused investigations to become more scientifically based. Now the investigation results that were once based on common sense are now formulated through the use of the "The Scientific Method." Use of the scientific method not only supports the findings of legitimate arson investigators it can also be used to discredit the findings of charlatans in the field.

The scientific method has been used in other areas of science for a number of years but has only recently been adopted by the field of arson investigation. The National Fire Protection Association defines the scientific method as "the systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of a hypothesis (NFPA, 2011)."

In the NFPA guide book, the scientific method, as applied to fire investigations, is broken down into six specific steps:

1) recognizing the need for the investigation;

2) defining the problem;

3) the collection of data;

4) analyzing the date (inductive reasoning);

5) developing a hypothesis regarding the cause;

6) testing the hypothesis.

In applying the scientific method to arson investigations it is possible to develop potential ignition scenarios for what may have caused the fire being investigated and then test each of them against the evidence as it is being collected (Ogle, 2003). The process of applying the evidence against the scenarios allows an investigator to consider far more options during the course of his investigation. Nearly every professional and technical organization involved in the field of arson investigation advocates the use of the scientific method in the investigation of fires and other catastrophic accidents involving fire.

The publication of the NFPA 921 guide book marked a dramatic step forward for the arson investigation field. It quickly became the pre-eminent resource in the field and brought the scientific method into the process lending creditability to the methods and conclusions of arson investigators. Most importantly, the guidelines established by NFPA 921 embodied every component of the reliability inquiry mandated by the Daubert case.

IV. Legal Considerations

The two leading cases setting forth the legal standards for arson investigators are Michigan v. Taylor (Michigan v. Tyler, 1978) and Michigan v. Clifford (Michigan v. Clifford, 1984). For the most part, Tyler set the basic standards for arson investigations with the Clifford case offering a few clarifications. In Tyler, the U.S. Supreme Court established that a warrant is not necessary when investigators are present as the fire is being fought and that investigators may remain on the scene for a reasonable time after the fire is extinguished to search for the cause of the fire. During their initial investigation, all evidence in "plain view" may be seized and deemed admissible. After an expiration of a reasonable time, investigators must either procure a warrant or obtain the permission of the property owner in order to continue their investigation. Clifford clarified a discrepancy that was unclear in the Tyler case. The Court in Tyler ruled that once investigators leave a scene, either as part of a warrant or as part of their initial investigation at the time of the fire, they must obtain a warrant. Also, Clifford established that any evidence constituting probable cause must be discovered in the initial investigation, pursuant to a valid warrant or the consent of the property owner.

In addition to following the legal standards set by Tyler and Clifford, arson investigators must be careful to coordinate their efforts with the prosecutor's office that will be handling any potential arson litigation. This cooperation included the proper collection of any evidence and developing a well founded theory of the case.

Finally, the investigator must be careful to pay special attention to detail and take notes relative to his investigation. Due to the difficulty in proving arson cases, testimony at trial is often required of the arson investigator in order to assist in establishing the elements of the case.

V. "Daubert Challenge

The Daubert Challenge arises out of the landmark U.S. Supreme Court case, Daubert v. Merrill Dow (Daubert v. Merrill Dow, 1993). In Daubert, the Supreme Court altered 70 years of precedent for the admission of expert evidence. Prior to Daubert the threshold standards for the admission of expert testimony were relevance and reliability. The Daubert reaffirmed the requirement of relevance in the presentation of expert testimony; however, it changed the standard of reliability.

The standard prior to Daubert was established in the case of Frye v. U.S. (Frye v. U.S., 1923). In Frye, the reliability standard was defined as "general acceptance" within the particular field or discipline involved in the testimony being offered. The Frye standard was considered to be both rigid and static and not sensitive to the rapid evolution of knowledge that was typical of most professional and scientific communities. The Supreme Court in Daubert expanded the measure of reliability and create a new standard based upon a broader analysis of the evidence. Under Daubert, the reliability of expert testimony is determined through a series of inquiries, including:

1) Has the theory or technique been tested under appropriate standards and controls?

2) Has the theory or technique been subjected to peer review?

3) Does the theory or technique have a known or potential rate of error?

4) Has the theory or technique gained "general acceptance" in the field or profession?

The Daubert case had a profound effect on the field of arson in that Daubert required that the methodology used must be a strictly scientific one and the subjective interpretations that were being used in many fire investigations were not strictly scientific. Fortunately, at the time that the Daubert case was being announced, the field of fire investigation was undergoing a significant evolution and the methodologies and techniques advanced by the publication of the NFPA 921 guide raised fire investigation to the level required by the Daubert decision.

VII. Evidence Spoilation

The term "spoliation" refers to the loss, destruction or alteration of an object which is either evidence or potential evidence in a legal proceeding. It is not unusual in a fire investigation to have evidence be subject to spoliation.

One of the first courts in the United States to attempt to define spoliation was the California Court of Appeals. In the case of County of Solano v. Delancy, the Court defined spoliation as:"…spoliation" means failure to preserve property for another's use as evidence in pending or future litigation (County of Solano v. Delancy, 1989)."

Arson investigations are particularly vulnerable to spoliation problems. The American Courts have been sensitive to these problems and have fashioned some special treatment for situations involving potential spoliation.

Obviously, the outcome of many legal cases turn on the existence or condition of physical evidence that is either not available or has not been properly preserved. In such circumstances, the defense or claim faces a strong likelihood of failure. Arson cases are the classic example of this principle. Too often, critical evidence in such cases is missing or severely damaged and, as a result, juries are left with only witnesses' descriptions or recollections to make a determination. In recent years, the courts have recognized the serious nature of situations involving spoliation and have begun imposing sanctions on parties who may have participated in spoliation.

The remedies employed by the courts include: (1) discovery sanctions, arising under the court's "inherent powers" or under the rules of discovery; (2) application of evidentiary inferences or limitations under the rules of evidence; (3) independent tort actions for the intentional or negligent destruction of evidence; and (4) prosecution under criminal statutes relating to the obstruction of justice.

There has, to date, been no universal application of the above mentioned sanctions. Different jurisdictions have adopted their own approach and, therefore, arson investigators must be cognizant of their particular jurisdictions' method of handling evidence in situations involving potential spoliation. Failing to do so may result in disastrous result for one's investigation.

For the reasons stated, spoliation should be a concern for every arson investigator or prosecutor involved in an arson related case. The practical effect of spoliation is the loss of importance evidence that may affect the outcome of the case. All legal cases should be decided on the evidence and when importance evidence is destroyed or altered this may not be possible. It is, therefore, incumbent on everyone involved in an arson investigation to exercise their best efforts to ensure that evidence is neither destroyed nor altered so that spoliation does not become an issue.

VIII. Conclusion

Arson is a major social problem that costs our communities, the taxpayers, and insurance companies millions of dollars every year. In a struggling economy arson becomes an attractive alternative for many businesses and individuals desperate to rid themselves of heavy mortgage payments, the costs of a failing business, or to a possibly profit from the insurance proceeds. The use of arson for these purposes is increasing and has reached almost epidemic proportions in some of America's largest cities. Despite improved technology, more professional investigator, and increased interest in attacking the problem there is no indication that the problem is lessening. A problem that was once thought to be the result of vandalism and pyromania has now become a vehicle of organized crime and profit seekers.

Due to the nature of the crime, arson remains a difficult crime to investigate and an even more difficult crime to prove. For the reasons stated herein, and for many others, it remains so but it is hoped that through the use of improved technology and new teaching methods for the investigators the problem will begin to diminish. Society can ill afford to witness the continued growth of arson and, perhaps, by increasing the criminal enforcement measures surrounding the crime those contemplating the act of arson may be dissuaded.