This is the sixth installment in “Exploring Integrity: Reviewing Wrongful Conviction Remedies,” a series examining the impact of conviction integrity units on the American judicial system’s rate of wrongful conviction. Presented by the O’Brien Fellowship in Public Service Journalism, the investigation is supported by Marquette University in Milwaukee, Wisconsin.
The meeting should have happened in 2008.
Detroit Fire Department Capt. Rance Dixon’s findings about a deadly eastside blaze could have potentially saved a man from being sent to prison if Dixon had spoken with a single witness.
But he didn’t know the witness existed.
Dixon, a former arson investigator, testified this week in a Third Judicial Court of Michigan hearing to determine if Mario Willis, convicted in the 2008 homicide of firefighter Walter Harris, will receive a new trial and possible exoneration. Dixon told Willis’s defense attorney Wolf Mueller that he only learned in court Dec. 10 — during Mueller’s questioning — that Darian Dove had confessed to accidentally torching the house, which caused Harris’s death.
After stressing the National Fire Protection Association 921 professional guidelines and method of determining fire cause and origin, which Dixon said he observed, Mueller referenced earlier testimony that Dixon wished he’d known about claims that gasoline was stored in the home.
“Yeah, I wish I would have known about Darian Dove, too,” Dixon said.
Once a handyman hired by Willis, Dove testified earlier in the hearing, disputing initial confessions that he took a woman to 7418 East Kirby Street and accidentally destroyed the house after starting a small fire to keep warm. Dixon acknowledged that he hadn’t been able to adhere to the highest standard of scientific methodology in fire investigation, since he was unaware that Dove had been in the home, and had no way to test Dove’s original story versus an arson theory.
Dixon filed a six-page report Nov. 16, 2008, the day after the fire, and made no supplements to his conclusion that the fire was deliberate. He testified that he didn’t even hear the name Darian Dove until three months after Willis’s trial, during which Dove fulfilled a plea bargain by saying Willis paid him to set the blaze, in order to collect an insurance policy payment.
“An expert’s opinion is only as good as the data to support it. Is that right?” Mueller asked Dixon.
Dixon agreed, saying that he never located any witnesses at the scene of the blaze, nor inquired whether police detectives located witnesses or suspects. Dove had told detectives he fled 7418 East Kirby and called the fire department. He said he “broke out crying” when he learned that Harris died after battling the flames.
Friday morning, Marc Fennell, an internationally renowned, Michigan-based fire investigator and analyst, testified, pro bono, as an expert in support of Willis, further challenging Dixon’s conclusion of arson.
“It’s undetermined,” said Fennell. “Absolutely it is, yes.”
Among several theories, in addition to the lack of Dove’s initial account of the accident, Fennell disputed Dixon’s association with the smell of gasoline at the scene with a deliberate burning. The “mopping up” process that firefighters use, including seeking “hot spots” after a fire is contained, plus other measures, involves gas-powered equipment, Fennell said. Ironically, equipment designed to help rescue Harris, who’d collapsed under the roof, might have even caused the odor, he added.
“It is mass chaos…faster than NASCAR at a pit stop,” said Fennell, an ex-firefighter.
Regarding Dixon’s testimony, Mueller asked Fennell: “He didn’t even do the first basic step of the scientific method — consider an alternative hypothesis. Fair?”
Fennell agreed.
Also discussed was the lack of an expert at Willis’s original trial. Fennell repeatedly testified that a qualified advisor to Willis’s lawyer, Wright Blake, would have been valuable to Willis’s defense in 2010.
“Clearly you would be able to tell a jury, based on common sense and your scientific background, that this fire was not incendiary,” Mueller asked.
“Correct,” Fennell replied.
Lack of follow-up documentation, such as photographs of certain areas of the 2008 scene, he added, also helped hinder proper conclusions about the tragedy that left Harris dead and sent Willis to prison.
“That’s why I don’t understand why, investigating fires, there’s such a rush,” said Fennell. “The fire’s not going anywhere. Do it right.”
Assistant Wayne County Prosecutor Amanda Smith began cross-examining Fennell before the hearing was adjourned until Jan. 7, 2026.
Since his conviction, Willis, 44, has served at the Saginaw Correctional Facility, where he remains incarcerated, pending the hearing’s outcome.
In 2023 the Wayne County Prosecutor’s Office Conviction Integrity Unit reviewed Willis’s case, but denied his request for exoneration.
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