Arson Science Under the Microscope Again

Sonia Cacy, who was convicted of murder based on questionable fire science, will return to court where a judge will determine if she should get a new trial.

By Comments

In 1993, Sonia Cacy was convicted of killing her uncle, Bill Richardson, by dousing him in an accelerant and burning him to death in their home in Fort Stockton. She was sentenced to 99 years, what essentially amounted to life in prison. But six years into her sentence, the parole board released her. Gerald Hurst, a leading fire investigator, had submitted a brief on her behalf, detailing the questionable evidence of arson used by the prosecution against Cacy. She moved to the coast last year, an attempt to start a new life, but since she has never been exonerated, she continues to be labeled as an ex-convict. But that could change next Monday when she returns to Fort Stockton where a district judge will look at her case and make a recommendation to the Court of Criminal Appeals about whether a new trial should be held.

As I detailed in a story about Cacy, one of the most troubling details about the evidence had to do with the testing of a clothing sample from Richardson’s body. Bexar County toxicologist Joe Castorena, who conducted the original testing of the scrap, testified that it was positive for traces of gasoline. Yet a different piece of his clothing, examined by a lab in Dallas, tested negative. And all of the lab scientists who have reviewed Castorena’s work concluded that he misread the results.

While researching this story, I discovered Castorena later made a perplexing claim to Cacy's attorney, Gary Usashen. According to Castorena, before he tested the scrap—the one that is now being questioned by other toxicologists—it had been contaminated in the morgue with xylene, a compound that can be found in both gasoline and other materials, like the foam mattress Richardson slept on. This contamination, he reasoned in a letter to Udashen, explained why those who interpreted the results after him had reached conclusions different from his own. But this begs the question that if the sample was contaminated in the morgue with the very same compound Castorena says indicates arson, can the results be trusted at all? Castorena did not respond to a message left at a number listed for him, or to previous requests for comment.

John Lentini, regarded as one of the fathers of modern arson investigation and one of the earliest arson experts to examine Cacy’s case, is aghast at Castorena’s claim. Lentini is a figure in arson science who commands attention when he weighs in on a case. His work on the 1990 Lime Street fire in Jacksonville, Florida, echoes through every investigation today. He had been hired by the prosecution to investigate a suspicious fire that claimed the lives of six people. Indicators like “pour patterns” on the floor—signs he’d learned indicate arson—were visible. A nearly identical house was abandoned a couple of doors down, so Lentini staged an experiment. He set fire to a couch, stepped back and watched the house burn. Flashover is the moment at which gases in the structure become so super-heated that everything inside simultaneously combusts. The abandoned place on Lime Street reached that point within five minutes and created the very same “pour patterns” he had always believed were caused by an accelerant.

“I was going to send a guy named Gerald Lewis to Ol’ Sparky for killing six people,” he recalled. “Being human, I was quite chastened by the results of the test.”

He’s spent the next two decades questioning the accepted wisdom of arson investigation, including the methods practiced during the testing of the Richardson clothing sample.

“Castorena should have rejected that sample if he knew it was contaminated and that should be the end of it,” Lentini said. And he's concerned with testing that was coming out of Bexar County at the time the clothing was examined, in part because Fred Zain, a serologist at the lab, was working there. Zain, who was Castorena's boss at the time, was fired in 1993 (the same year Cacy was convicted) for falsifying the results of blood tests. The charges against him resulted in the wholesale re-examination of hundreds of convictions based on his work.

But even if you dismiss the dysfunction at the lab, Lentini said, Castorena’s claims still don’t add up. If the sample was contaminated with xylene, a compound you’d expect to find in any house fire, accerlerant or no, the concentrations should be “off the charts,” he said. Yet it’s present at the same levels as another common pyrolysis compound, toluene. “Castorena says ignore the xylene because it’s contaminated and ignore the toluene because it comes from pyrolysis products [compounds that result from burning plastics and other materials] and just look at the rest of the chart,” he said. Also, many of the compounds singled out by Castorena as evidence that gasoline was present are accompanied by what are known as alkenes. These are markers for burning polyethylene (plastic) and asphalt. Lentini emphatically disputes Castorena's findings. “He doesn't have any evidence of gas, and there has been a dozen forensic scientists who read gas chromatograms for a living and look at this and say ‘No gas.’,” Lentini said. “Nobody gives this any credence at all, and I think the DA is going to give up on it.”

In fact, the expert hired by the district attorney in Fort Stockton, Rod Ponton, reached the same conclusion. Ponton now appears to be building his case against Cacy based on circumstantial evidence versus forensic evidence, and Lentini is bearish about Ponton's chances. “Ponton called me up and asked me to work for him," Lentini said. "He told me which case it was [Cacy’s], and I said I have two affidavits on this case already.”

Related Content