Defendants in arson cases around the U.S. are challenging their convictions as new research has blown holes in investigators’ long-held assumptions about how fires start and spread, reports the Wisconsin State Journal in the last of a series. Many of those investigators work for insurance companies with a stake in the outcome. John Lentini, a prominent fire investigator and one of the harshest critics of the current state of fire science, said some of the probes amount to little more than “witchcraft and folklore.”
Unlike improvements in DNA technology, which have helped police solve more crimes, advances in fire investigation may have had the opposite effect: As knowledge about fire grows, uncertainty about the origin of fires has increased and the number of fires declared intentional has plummeted. Since 1980, the number of intentionally set fires has been on “a long-term downward trend,” currently accounting for about 8 percent of all structure fires, down from about 20 percent 30 years ago, the National Fire Protection Association reported. Roughly half a million U.S. buildings are damaged or destroyed by fire each year.