Updated

A man who has spent more than three decades in prison after he was convicted of starting a fire in 1982 that killed eight people, including five children, has been granted a new trial.

In a 99-page ruling issued this week, a Middlesex Superior Court judge cited developments in fire-science investigation and questions about whether the Victor Rosario's confession was voluntary in her decision to overturn his arson and murder convictions.

Attorneys for Rosario, 57, argued in March that there were serious flaws in the investigation that led to his 1983 conviction in the Lowell blaze. He was stencned to life in prison.

"We are both very pleased with the judge's decision," Lisa Kavanaugh, one of Rosario's lawyers, told The Sun of Lowell. "We feel that it reflects a well-reasoned recognition of a number of important discoveries that have been made since the time of Mr. Rosario's 1983 trial in the areas of fire science, medical issues affecting voluntariness and interrogation techniques now known to contribute to false confessions."

The Middlesex district attorney's office said in a statement that it is still weighing the judge's decision and considering whether to lodge an appeal.

Retired arson investigator Harold Waterhouse, 84, who investigated the fatal fire, called the judge's decision "ridiculous" and said he stands by his original findings.

Prosecutors said Rosario, who remains imprisoned, and two brothers, who have since died, set the fire by throwing Molotov cocktails at the building as payback for a botched drug deal. The eight victims included five children as well as the man prosecutors said the suspects were targeting. The brothers were charged but never tried because Rosario refused to testify against them.

Among the problems with the investigation cited by Rosario's attorneys was the lack of an accelerant and burn patterns that do not necessarily indicate arson.

They also said there were translation problems with the Spanish-speaking Rosario and said he was delusional when he confessed during questioning and claimed he was Jesus Christ.