Fire investigation is the process of examining fire-related incidents to uncover where the fire started (the origin) and how it started (the cause). Anyone can and should take precautions to reduce the risk of an accidental fire and should protect their possessions and property. However, not all fires are started by accident; intentional fires could be started at any time so it is important to be prepared.
If a fire investigator believes the fire was started intentionally, it may lead to criminal charges, and in cases involving deaths, the person responsible could face murder charges. However, determining whether a fire is accidental or intentional can sometimes be challenging as investigators may have to reach beyond the scope of their investigation to make that determination. In the forensic science world, when an investigator receives information beyond their scope, it is believed the investigator or analyst can fall victim to bias.
Over the years, the methods used to investigate a fire have greatly improved, dispelling many old myths and reducing the impact of bias in an investigation.
The Outdated “Method”
Before 1992, there was no standardized guide for investigating fires, and fire investigators didn’t have specific education requirements. Early investigations relied on methods passed down through generations, based on observation and intuition rather than science. Indicators of intentional fires, like burn patterns or the presence of accelerants, went unquestioned. Unfortunately, these methods led to incorrect conclusions and numerous wrongful convictions.
Before using a scientific-based method, investigators would interpret certain “evidence” as signs of intentional fire setting. For example, the presence of “crazed glass” was once considered evidence of the presence of an accelerant and used to convict individuals of arson. However, one of the nation’s leading fire scientists, John Lentini with the help of other fire scientists later discovered crazed glass was caused by rapid cooling and not the presence of an accelerant. This led to a reexamination of cases where someone was wrongly convicted based on these observations and old myths.
The Use Of The Scientific Method
In 1992, the National Fire Protection Association published A Guide for Fire and Explosion Investigation, commonly referred to as NFPA 921. Authored by leading experts in the field, NFPA 921 introduced the scientific method to fire investigations. Initially met with resistance, by 2000, NFPA 921 became widely accepted as the standard for proper fire investigation. Scientific research and experiments have enhanced our understanding of fire behavior, though challenges remain in accurately identifying the origin and cause, especially in large-scale fires with extensive damage.
Despite advancements, the fire investigator’s ability to correctly identify the origin of a flashover fire (when a fire in a room becomes a room on fire) is still unknown. This is problematic because, as addressed in the 2016 President’s Council of Advisors on Science and Technology (“PCAST”), jurors are often misled by an expert when a true error rate relating to a scientific conclusion is unknown.
Other changes include the need for a positive laboratory test before a fire investigator can testify to the presence of an accelerant. Additionally, fire investigators are now required to undergo specific training and education, as outlined by NFPA 1033:Standard for Professional Qualifications for Fire, ensuring competence in their work.
Wrongful Arson Convictions
Innocence projects have reviewed numerous arson convictions, revealing major flaws due to the use of junk science and myths in fire investigations. In fact, of the 3,459 exonerations reported, about 85 were wrongful arson convictions, with more than half of those wrongful convictions caused by false or misleading fire investigations. (National Registry of Exonerations, 2023.)
A 2012 exoneration in Michigan showcased the importance of new scientific research in proving innocence, overturning David Lee Gavitt’s 1985 conviction. New fire experts concluded that a flashover (a phenomenon where a fire burns to eventually explode and engulf an entire room) occurred in Gavitt’s residence, killing his wife and children. We now know once flashover occurs, interpreting the fire patterns becomes difficult and often leads to incorrect conclusions about the fire’s origin and cause. This played a pivotal role in his conviction. Also found in Gavitt’s case was the improper conclusion that gasoline (an accelerant), was found in the house. Lentini reviewed this case and said in an affidavit that the experts “bundled [arson] myths together” and “in light of modern fire science, there is simply not one shred of credible evidence that the fire. . . was intentionally set.”
Similarly, in 2014, the Supreme Judicial Court of Massachusetts overturned Victor Rosario’s case, stating “had the new fire science evidence been available at the time of trial it . . . could have provided a basis for the jury to question … how the fire developed.” (Possley, M., 2021.)
However, not all states immediately embraced the new scientific understandings in the fire investigation field. The case of Cameron Todd Willingham in Texas, convicted based on outdated myths, led to his execution in 2004 despite later evidence proving the forensic fire testimony was incorrect. Similarly, the courts in California rejected Joann Parks’s claim that the 1989 investigation of a fire that took the lives of her three children was accidental and her conviction was based on outdated science and extreme bias. The Innocence Center’s Director of Litigation, Raquel Barilla, worked on Parks’s case for many years, gaining expertise in the area of fire investigation. Although the court failed to conform to the changes in the science, Parks was released after Governor Newsom commuted her LWOP sentence, allowing JoAnn to be released on parole. To learn more about her case and the problems with forensic “junk” sciences and fire investigation, you can buy Edward Hume’s book Burned.
Every year, innocence projects revisit arson cases, leading to more exonerations as new scientific research continues to expose wrongful convictions.
