Even before the inferno that engulfed the Maui resort of Lahaina is fully contained, local officials and Hawaii’s leading utility are at odds over a fundamental question: Did a single fire break out in the hills overlooking the town on the fateful day, or were there two?

The answer may be crucial to establishing the cause of the disaster and the liability for it.

The utility, Hawaiian Electric, acknowledged for the first time late Sunday that its power lines, buffeted by uncommonly high winds, fell and ignited a fire early on the morning of Aug. 8.

But the company said that by 6:40 a.m. — minutes after the first reports of a fire — the windstorm had caused its lines in the area to shut off automatically. And it noted that the fire was later reported “100 percent contained” by the Maui County Department of Fire and Public Safety, which left the scene and later declared that the fire had been “extinguished.”

And Hawaiian Electric said its lines were carrying no current by the time flames erupted in midafternoon and quickly consumed much of downtown Lahaina and killed at least 115 people. The cause of that fire, the utility said, “has not been determined.”

That account — referring to a “morning fire” and an “afternoon fire” — was a rejoinder to a lawsuit filed on Thursday by Maui County, which criticized the utility for negligence in failing to maintain its equipment and accused it of not cutting off the electricity. The lawsuit followed several others filed by lawyers for wildfire victims.

“We were surprised and disappointed that the County of Maui rushed to court even before completing its own investigation,” Shelee Kimura, president and chief executive of Hawaiian Electric, often referred to as HECO, said in statement responding to the Maui County lawsuit. “We believe the complaint is factually and legally irresponsible.”

John Fiske, a lawyer representing Maui County in the lawsuit, said Monday that the burden remained with the utility to show that its equipment was not responsible for the devastation, given the recognition that the day appears to have begun with a fire caused by power lines. The lawsuit refers to a single Lahaina fire, along with two fires elsewhere on the island.

“To the extent HECO has information of a second ignition source, HECO should offer that evidence now,” Mr. Fiske said. “The ultimate responsibility rests with HECO to de-energize, ensure its equipment and systems are properly maintained, and ensure downed power lines are not re-energized.”

Fire investigators with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives are working to determine the cause of the fires that burned through the town on Maui’s west side. The agency, which includes members of its National Response Team from Honolulu and Seattle, declined to comment on Monday about the status of its investigation.

Maui County reported that the Lahaina fire was 90 percent contained and had burned 2,170 acres. The county also reported that two other fires were also almost completely contained: the Olinda fire, which burned 1,081 acres and was 85 percent contained, and the Kula fire, which consumed 202 acres and was 90 percent contained.

Hawaiian Electric quickly became the focus of the wildfires on Maui as evidence pointed to its equipment as the cause, angering some who criticized the company for the poor condition of many of its electrical poles and for failing to use the kind of power shut-off program that California utilities have adopted for fire prevention.

Until its statement late Sunday, Hawaiian Electric had left a lot unsaid. The company largely spoke of efforts to restore power in Maui County, where it provides electricity to about 74,000 of its almost 500,000 customers across five of the state’s islands.

The Lahaina fire began about 6:37 a.m. Aug. 8, near Lahainaluna Road on the hill above the downtown, according to the county lawsuit. It was fueled by strong winds that swept violently down from atop Haleakala, a heavily forested, mountainous area known as “Upcountry.”

“We had almost like a wind tunnel,” Rudy Tamayo, vice president of energy delivery for Hawaiian Electric, said in an interview last week before this reporter rode with utility crews working to restore power in the area.

Sheryl Nakanelua, 55, lives near the first ignition point just off Lahainaluna Road. She wakes up every morning about 3:30, she said, and she recalls the unusual winds, even for blustery Maui. Debris flew into her yard, including street signs and parts of trees, forcing her to spend five days clearing it all.

“I felt 45-mile-per-hour winds before, and it was nothing like that,” Ms. Nakanelua said. “It had to be like 60 to 80 miles per hour. It was pushing me back.”

The power went out, came back on and then went out again about 10 minutes later, she said. That was in the 6 a.m. hour, when she also noticed smoke a block away and then flames. That was when she and her neighbors on the hill fled, as the torrential winds shook their cars.

It was those winds that Hawaiian Electric said had knocked down power poles and line in Lahaina, causing the early-morning fire. About 6:40 a.m., the power went out, the utility said.

“The windstorm caused the power to ‘trip,’ meaning it shut off automatically,” said Jim Kelly, a spokesman for the utility. “Hawaiian Electric didn’t shut it off manually.”

The potential threat of winds to equipment has been a concern of Hawaiian Electric, which noted in an Integrated Grid Planning Report in May that it was evaluating wind speed design policies. The utility said it had designed structures to withstand wind loads consistent with the standards prescribed in the National Electric Safety Code for 2002.

Jennifer Potter, a former commissioner on the Hawaii Public Utilities Commission who left the agency in November, said upgrades to the electric grid throughout the state should have been made long ago.

“This tragedy should be a wake-up call to the rest of the utilities across the country,” Ms. Potter said.

The west side of Maui is powered by three high-voltage transmission lines, a mix of metal and wooden poles that feed into two substations and the poles and wires that connect to homes and businesses.

Hawaiian Electric intends to carry out a number of upgrades, Mr. Kelly said, like replacing copper wires with less-brittle aluminum, making poles more fire-resistant, installing sensors and cameras to detect equipment problems, and adding more automatic shut-off mechanisms.

For now, workers have brought a mobile substation to the town to replace one in downtown Lahaina that was lost to the fire. Working 12- to 16-hour days, crews have also erected poles and run fresh wire to get electricity back to those who remain in and near Lahaina.

The mobile unit can’t provide service for an entire town, but it supports a line that the workers restored for critical service along Honoapi’ilani Highway for those still in Lahaina and in nearby communities like Olowalu.

It could be some time before the Lahaina substation gets full repairs, as little plumes of smoke continued to waft from a burn area next to it, with some embers still smoldering.