A man executed for a deadly house fire may have been wrongly convicted on faulty science that may taint other US fire investigations, according to experts working with an activist group that is asking for a study of such cases.
The Texas man was executed in 2004 for a fire that killed his three little girls. Fire experts say he was wrongfully convicted because junk science was accepted as expert testimony.
More than 5,000 people are imprisoned in the US for arson, and at least some are likely to have been wrongfully convicted, said five experts who analyzed testimony in the Texas case.
The experts included veteran arson investigators and people with backgrounds in science and engineering who have taught other investigators.
"It's an unspeakable error and people don't want to admit they made that error," said John Lentini, one of the arson experts.
Lentini and his colleagues concluded bad science was at the heart of the testimony that led to Cameron Todd Willingham's conviction for a 1991 fire in Corsicana, Texas. Willingham maintained his innocence up to his execution in 2004.
The expert panel, along with The Innocence Project, a New York-based group that seeks to uncover wrongful convictions, presented their study last Tuesday to a special Texas commission set up to examine forensic misconduct.
The problems with arson convictions could be huge. The Innocence Project commissioned the panel to study Willingham's case, but said its network of state projects around the country has already begun to review other arson convictions.
"It's really hard to get a number of how many people have been falsely accused, falsely convicted, falsely excluded from insurance payment," Lentini said. "A hundred? A few hundred? Impossible to guess, without study of the evidence that convicted them."
Willingham's case stands out because he was executed. A few others are now on death row for arson murders, but the majority are serving prison terms. The Bureau of Justice Statistics counted 5,405 people imprisoned as of 2002 for arson, but that only collected data from just over half the states.
Among the flawed ideas that were part of the testimony against Willingham was the idea that gasoline-fueled fires burn hotter than wood fires, and melted aluminum in the house proved it was intentionally set. However, gas blazes aren't necessarily hotter, the experts said.
A theory that "crazed" glass, a spidery cracking of glass, which investigators testified proved the presence of a hotter fire caused by an accelerant like gasoline. Experts now believe that cracking may take place when water is sprayed during firefighting, or if the glass is struck.
Also, investigators testified that the fire had "multiple origins," which would imply that it was intentionally set. The experts who reviewed the testimony said there was no credible way to determine that.
Those ideas were "a hodgepodge of old wives' tales" accepted as fact without any scientific support, said Gerald Hurst, a private arson investigator trained as a chemist.