Arson cases are being challenged more often as uncertainty about the origin of fires has increased.

Around the country, defendants in arson cases are challenging their convictions as new research has blown holes in investigators' long-held assumptions about how fires start and spread.

As in the investigation into the fire that destroyed J.J.'s Pub in rural Marquette County on Sept. 11, 2006, 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."

He cited a 2005 test designed by the U.S. Bureau of Alcohol Tobacco and Firearms in which fire investigators were asked to identify the general area where two test fires were started in separate rooms. The fires were extinguished less than three minutes after achieving "flashover" — the point when, Lentini says, "a fire in a room becomes a room on fire."

Each time, just three of the 53 investigators got the area of origin right, and it was a different three each time, Lentini said. Subsequent tests have produced similar results.

Another series of test burns in 2008 called into question the widely held belief that V-shaped burn patterns on walls — like the one cited in the arson case against J.J.'s Pub owner Joseph "Joey" Awe —indicate where a fire started. In fact, the markings "bore no relationship to either of the fires' origins, which were approximately six feet from the apex of each ‘V,'" the bureau reported.

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 last year. Roughly half a million buildings in the United States are damaged or destroyed by fire each year, the NFPA estimates.

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