Florida-based John Lentini, one of the best-known fire investigators in the nation, agrees. “What we had was a bunch of guys who claim to be expert fire investigators telling a jury that they can see multiple origins,” Lentini says. “Quite frankly, I couldn’t see that.” The investigation of the Lone Star Guns fire was typical, he says. “It’s an appealing notion that you can calculate multiple points of origin. This school of thought hasn’t been validated, and it leads to false convictions.”In that case:
Two of the leading arson experts in the country believe the fire at Lone Star Guns was accidental. They say it had a single point of origin, sparked by a frayed electric cord found at the scene, and was spread by a case of aerosol cans sitting nearby. The cans were filled with highly flammable gun cleaner. When aerosol cans explode, they can act like blowtorches, spewing flaming liquid all over. These experts say the ATF agents, using sloppy methods, mistook an aerosol-can explosion for a three-point-of-origin fire.
“Spray cans can create the illusion of multiple origins,” says Gerald Hurst, an arson and explosives expert who lives in Austin. “Arson investigation always has one basic tenet. You have to eliminate all reasonable natural and accidental causes of the origins of the fire.” In Severns’ case, “There is no way in hell you can eliminate those spray cans.” ...
Over the past 15 years, many unscientific assumptions about how fire spreads—inherited knowledge passed from one generation of investigators to another—have turned out to be wrong. Using newer methods, Hurst has helped exonerate dozens of people wrongly convicted of arson, including two infamous cases in Texas, and has helped save several defendants from the death chamber. He believes [Curtis] Severns was railroaded. As Hurst put it at Severns’ 2006 trial in Sherman when asked how the fire spread, “If that’s not a spray can, I’m a monkey’s uncle.”
Read the whole thing and watch a video demonstration by the ATF of what happens when aerosol cans burn - evidence that contradicts "expert" forensic testimony put on by the prosecution at trial.
See also an Innocence Project of Texas fact sheet about good legislation that would help inmates convicted based on now-discredited forensics, particularly arson, get back into court via post-conviction writs.
- Many arson convictions based on invalid science
- Arson convictions may be next venue for innocence claims
- College to develop screening processes for vetting old arson cases for bad forensic science
- Forensic Science Commission to investigate faulty forensics in Cameron Willingham case
- Improving access to post-conviction writs for junk science