PORTLAND, Maine — Landlord Gregory Nisbet was found not guilty on all counts of manslaughter arising from the deaths of six young adults in the state’s deadliest fire in decades.

Nisbet, 51, also was acquitted of all but one of the misdemeanor charges against him. The court found him guilty of a single fire code violation because the windows on the third floor of his building at 20 Noyes St. were too small to offer a second means of escape in the 2014 fire at Nisbet’s Portland property.

Several relatives of the victims walked swiftly out of the courtroom as the verdict was issued.

“No justice was served today,” said David Bragdon, the father of one of the victims, David Bragdon Jr. He was headed to the courthouse when the verdict was handed down. Other family members declined to comment as they hurried out of the courthouse, brushing away tears.

In issuing his verdict Friday, Cumberland County Superior Court Justice Thomas Warren said that the six deaths ”were beyond tragic.” But the court could not find “beyond a reasonable doubt” that the deaths would not have occurred but for Nisbet’s actions, he said.

Nisbet, who did not speak publicly at the trial, left the courtroom through a private exit after being embraced by several supporters.

A sentencing hearing will be scheduled in the next couple weeks, Warren said.

Nisbet could face as much as six months in county jail and a $1,000 fine on the misdemeanor conviction, according to his lawyer, Matthew Nichols. Nisbet may speak at the hearing, Nichols said.

The landlord has been “through two years of hell” and expressed remorse privately, Nichols said. That sorrow “is going to be with him for the rest of his life, and I realize it’s more pain for the friends and family, especially the kids, but Greg has not been spared,” said Nichols.

Warren issued his verdict after a week of testimony in the courtroom and two weeks of deliberation. The decision also comes two weeks before the anniversary of the 2014 fire that killed David Bragdon Jr., 27, Ashley Thomas, 29, and Nicole Finlay, 26, who lived at 20 Noyes St., and visitors Steven Summers, 29, of Rockland, Maelisha Jackson, 23, of Topsham and Chris Conlee, 25, of Portland.

A memorial for the victims is planned for 1-4 p.m. Sunday, Oct. 30, in Portland’s Longfellow Park.

Like the blaze itself, Nisbet’s prosecution was historic. Landlords are rarely brought up on criminal charges in Maine, and even the single conviction may set precedent for how the justice system approaches landlord-tenant cases.

Nisbet, who requested that the complex case be ruled on by a judge rather than a jury, did not testify in his own defense during the trial. But the court heard testimony from nearly a dozen other witnesses — including harrowing accounts from survivors who narrowly escaped the fire.

The details contested by Nisbet’s defense attorneys and the state prosecutors included how hot and fast the deadly fire burned, the size of the windows in 20 Noyes St.’s third floor and how they opened, and how quickly the survivors exited the burning building.

But the question that appeared most central to the case was what type of dwelling the Portland duplex was and what legal obligations Nisbet had to his tenants.

Although the fire was accidental, state prosecutors contended that Nisbet was responsible for the six deaths because he should not have allowed residents to live on the third floor — which the prosecution called a “death trap” — and because he allegedly failed to keep his building up to the safety standards of a boarding house. Nisbet gave top-floor residents rope ladders in case of an emergency, according to the prosecution. Three of those who died in the fire were found on the third floor.

The fire was kindled by a stray cigarette butt, which ignited a chair and couch on the front porch of the building, investigators found.

After the deadly blaze, a fire inspector found the duplex to be a boarding house. But Nisbet’s lawyers argued that the inspector lacked crucial information at the time of the determination and that the residence was legally a single-family home, even though the residents were not related. State housing code has more strict requirements for means of escape in a boarding house than a family home.

“It is almost certainly true that if certain of the rooming codes had been in place … most or all of the occupants who died would have escaped,” said Warren. “But the court does not find that the defendant was reckless or criminally negligent in not recognizing that 20 Noyes had evolved into a lodging or rooming house.”

During the trial, a Portland building inspector testified that in 2012 he had responded to a complaint of an illegal dwelling on the third floor of the 20 Noyes St. home but didn’t go inside to investigate. And in the wake of the six deaths, Portland and other communities around Maine upped their standards for building inspections and fire safety.

In 2015, the Portland City Council voted unanimously to create the Housing Safety Office. The new office keeps a registry of rental properties and employs three full-time housing inspectors to enforce code.

State prosecutor Bud Ellis said that he and the victims’ families were disappointed at the verdict, but simply bringing that case may have made Maine tenants safer by making landlords more attentive to building safety. This idea was echoed by Nisbet’s legal council.

“This prosecution has put every landlord within shouting distance on notice. They don’t want to go through two years of hell,” said Nichols.

Maine landlords who had been closely watching the case found solace in the acquittals, according to Brit Vitalius, president of the Southern Maine Landlord Association.

“Rental owners are relieved to hear that Mr. Nisbet has been found not guilty,” said Vitalius.

But for Nisbet and the many other family members of the deceased who gathered in the Portland courtroom Friday, Warren’s verdict does not mean an end to the legal fight over the Noyes Street fire.

The estates of five of the six victims also have brought civil suits against Nisbet.

BDN writer Stephen Betts contributed to this report.