How many innocent people are behind bars due to faulty arson investigations?

Texas - The National Fire Protection Association issued its first set of fire investigation guidelines in 1992. Before then, fire investigators did not always use uniform procedures, Connealy said. Also, advances in scientific analysis have found other explanations for burn patterns once considered to be signs of arson.

The Innocence Project, a national legal reform group that has worked to exonerate more than 250 convicts, has identified potentially problematic arson cases in several states, including one in Tucson, Ariz., in 1970 in which 29 people were killed.

In Texas, which has had to free more than 100 inmates wrongly convicted in criminal cases, the state Innocence Project has narrowed its working list to about 60 arson cases of the 1,000 reviewed, chief counsel Jeff Blackburn said. A state expert panel, the Texas Forensic Science Commission, has also made 17 recommendations for improving how arson cases are handled.

The widespread attention given the Willingham case has driven interest in looking at other arson-related convictions. The Forensic Science Commission investigated the case for years, but was barred by Attorney General Greg Abbott from issuing a final report. Arson experts hired by the commission found the 1991 fire was most likely accidental.

It's possible that problems will be found with more cases, Connealy said.

"Having been around fire investigations and being in the fire service the last 35 years, I saw where there could be improvements," Connealy said in an interview. "I wanted to try to lead that effort to improving fire investigations. It should be based on science."

If the group finds problems with an arson investigation, its findings will be sent to the authorities with jurisdiction over the case and to the Texas Court of Criminal Appeals, Connealy said. No action will be required, but the report could help someone who is wrongly imprisoned.
http://abcnews.go.com/US/wireStory/arson-convictions-challenged-fire-science-18778561#.UVDGX97D-Ul