Arson Cases Show the Need for Better Training in Forensic Sciences

John Lentini

John Lentini is a fire investigation consultant and author of “Scientific Protocols for Fire Investigation.”

UPDATED MARCH 31, 2015, 6:45 AM

Although the situation has improved dramatically since 2000, fire investigation is a forensic science discipline that still lags far behind the rest of forensic science. This is largely because the people who become fire investigators generally lack the fundamental scientific education necessary to understand fire. We recruit our fire investigators from the ranks of police officers and firefighters, and while these are honorable professions, they require no scientific background.

We need higher salaries to attract more qualified people. Courts need to be more skeptical about poorly educated investigators.

Every day, we ask fire investigators to make sophisticated decisions about chemistry, heat transfer, fluid dynamics and electricity. We can provide training, but training is of little help when the person being trained does not have even a basic understanding of the underlying science. Voluntary certification programs exist, but there is no evidence  that certified fire investigators are any more reliable than non-certified investigators.

Fire is a chemical reaction resulting in the release of energy in varying intensities, yet many certified fire investigators with decades of experience are unable to name the basic units of energy or power.

Finding the origin of a fire is supposed to be a fire investigator’s core competency. Determining where a fire started, however, is a complicated task, and one that has a high error rate, unless the fire is extinguished in its earliest stages. The profession is just beginning to understand the effects that ventilation, or the lack thereof, can have on the fire damage. The problem becomes worse when the fanciful arson determinations of unqualified individuals are presented to courts.

Prosecutors, judges and juries have no way of knowing just how weak some of the fire science is, and the problem is exacerbated by the way that trials proceed. The prosecutor leads off with motive and character assassination. By the time the jury hears the bad science, they already hate the defendant and just don’t care that the allegedly scientific determination of origin and cause is invalid. That is exactly what happened in the trial of Cameron Todd Willingham, who was executed for setting a fire that killed his three daughters based on confident, but wholly inaccurate testimony by fire investigators. None of the so-called arson indicators relied upon had any validity.

The Willingham case owes its high profile to death penalty activists, but it is by no means the only miscarriage of justice that resulted from accidental fires being erroneously classified as intentional. Citizens who have been wrongly prosecuted for arson number in the dozens, if not in the hundreds.

To remedy this situation we need a more highly educated applicant pool, which means we need to be willing to pay higher salaries to induce more qualified people to join the field. And courts need to be more skeptical about the ability of poorly educated investigators to correctly determine the origin and cause of the fire. When the cause of the fire is not obvious, courts should be willing to entertain reliability challenges, and to provide funds for defendants to retain independent experts.

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Topics: Courts, crime, criminal justice, forensic science


William Case

Texas 20 hours ago

Critics faulted the Corsicana Fire Department arson investigator in the Willingham case for not following National Fire Protection Association arson investigation guidelines. However, in court hearings following Willingham’s 2004 execution, the critics admitted that the guidelines has not been published in 1991, when the arson investigation was conducted. The guidelines were first published in 1992. The critics primarily faulted the arson investigator for listing separate points of origin as one of about a dozen indications of arson. Willingham had set one fire in the hallway leading to his daughters’ bedroom and a second fire at the front door. (Prior to setting the fire, he had pushed a refrigerator to block the back door which led from the kitchen i to the back yard.) The critics pointed out that an extremely hot fire can mimic separate points of origin by causing flames to “flash” to other parts of buildings. However, firemen said that the Willingham fire wasn’t a “hot fire” and witnesses say they saw smoke but no flames. It took firemen only a few minute to extinguish the flames. After the Willingham case became controversial, the fire department hired independent arson investigators to go back over the forensic evidence using the latest guidelines. They concluded it was arson. Willingham’s defense also hire its own arson investigator, but did call him to testify at the trial because he also determined the fire was deliberately set.



Yeah, that’s why this case is the poster child against capital punishment. Try reading the report cited in the article. It won’t take long – no need to go beyond the first sentence that states that it wasn’t arson.


Bay Area

I am not sure where you have collected these “facts”, but I would recommend a New Yorker article ( In a “scathing” report, the fire scientist hired by the commission established by the Texas government to investigate the case “concluded that investigators in the case had no scientific basis for claiming that the fire was arson, ignored evidence that contradicted their theory, had no comprehension of flashover and fire dynamics, relied on discredited folklore, and failed to eliminate potential accidental or alternative causes of the fire. He said that… the approach [of the deputy fire marshal investigating the case at the time] seemed to deny ‘rational reasoning’ and was more ‘characteristic of mystics or psychics.’ What’s more, [he] determined that the investigation violated… ‘not only the standards of today but even of the time period.'” It appears that Willingham was executed for a ‘crime’ that never happened. In addition, last week the “the State Bar of Texas filed a formal accusation of misconduct… [including] obstruction of justice, making false statements and concealing evidence favorable to Willingham’s defense” against the county prosecutor who convicted Willingham (….