BOSTON – Attorneys for a man convicted of setting Lowell’s deadliest fire in decades plan to ask a judge to order a retrial after a report called into question some key aspects of the police investigation.

A report by the New England Center for Investigative Reporting published Sunday in The Boston Globe found Lowell police relied on assumptions about evidence that have now been discredited in determining arson caused the 1982 fire, which killed eight people, including three babies.

Victor Rosario, a 24-year-old bystander, was detained and confessed that he and two friends threw Molotov cocktails into the building as revenge for a botched drug deal. However, investigative records showed no accelerant or other evidence of Molotov cocktails was discovered, the report found.

He now insists he is innocent.

“I know in my mind, in my soul, I was never capable to do something like that,” he said in a prison interview.

Two lawyers plan to seek a new trial this summer.

But the lead Lowell investigator, Harold Waterhouse, who retired in 1989, insists the fire was arson and that Rosario did it.

“I don’t care about the new questions that have surfaced,” he said. “I don’t care about these experts. I’ll go to my grave with Victor being guilty.”

Fire experts say the absence of an accelerant should have caused police to reconsider their theory, the New England Center for Investigative Reporting said.

“If a fire is arson, it’s not a subtle crime,” said fire scientist John Lentini, who was an expert witness for Rosario’s legal team. “Particularly a place that’s been set with three Molotov cocktails, you’re going to find this stuff, you’re going to find gasoline and you’re going to find Molotov cocktails — and they found none.”

A translator who helped the police interrogation has reversed the account he gave at trial. In a sworn affidavit provided to Rosario’s current lawyers, he said Rosario was delusional during questioning and did not understand what he was signing.

Rosario was convicted of arson and eight murders within a year of the March 5, 1982, fire. He was sentenced to life in prison.

Arson experts who re-examined the trial record say almost all the evidence police cited also was consistent with an accidental fire, the investigative reporting group said. Investigators did not seriously consider possible accidental causes, such as a space heater, the center for investigative reporting said.