A week after a gunman opened fire in a neighborhood bar and vanished into the woods of western Montana, some residents in the small town of Anaconda jump at the sound of a door knock. Others are leaving their dogs outside to bark at anything unusual.

Law-enforcement helicopters buzz neighborhoods, and drones skim treetops as a sprawling manhunt for the suspect, a local Army veteran accused of killing four at the bar, continues on the fringes of the old copper-smelting town. At night, police searchlights trace across quiet country homesteads.

“The only thing people are talking about is this,” said Celina Van Hyning, director of Anaconda’s chamber of commerce.

A lengthy manhunt is unusual in the kind of crime that the authorities accuse the suspect of carrying out — a shooting in a public place or one that the public can enter, like a restaurant, workplace, school or place of worship.

Experts who study such shootings, which usually end in the capture or death of the gunman — either at the hands of the police or by suicide — were hard-pressed to find a parallel.

“One thing that sets this case in Montana apart from most other mass public shootings is the location,” said Jaclyn Schildkraut, executive director of the Regional Gun Violence Research Consortium at the Rockefeller Institute of Government. She cited the small, remote town, with rugged terrain and sparse population.

“In more urban and suburban areas” where most mass shootings occur, Ms. Schildkraut said, “you also often have faster law enforcement response, which prevents them from being able to flee in the first place.”

The authorities in Montana have tried to reassure Anaconda residents that they can get on with their lives while also remaining vigilant. But a week into the search, with no sign of the suspect since last Friday, normalcy feels more and more out of reach.

Hikers who would detour through Anaconda as they trek across the Continental Divide Trail are bypassing the town. Some portions of the nearby national forest have been closed. Banks have shuttered their lobbies. One sports bar locked its doors and asked customers to call to be let inside.

Anaconda’s tourism office even decided to cancel the annual Smeltermen’s Day festival that celebrates the town’s history as a center of copper smelting.

Ms. Van Hyning, the chamber of commerce director, said some people were worried about attending a large public gathering. Others felt it was not the moment for a weekend of parades, foot races and block parties.

Many in town knew the slain bartender, Nancy Kelley, 64, a former nurse, and the three patrons: Daniel Baillie, 59; David Leach, 70; and Tony Palm, 74. Others knew the suspect.

“It’s just not a time for celebration,” Ms. Van Hyning said. “It’s still really fresh and raw.”

The search effort was visible on Thursday along the gravel Stumptown Road, just west of Anaconda, where officials have said the suspect was last located. Dozen of cruisers from law enforcement agencies across Montana were parked there.

Some officers paced through meadows and aspen groves, while others roamed the dirt roads in off-road buggies. One resident held up a pistol as he drove up a dirt road to check on his nearby property. “I’m taking precautions,” he said.

Officials have said the suspect in the Anaconda killings, Michael P. Brown, 45, is likely still armed. He eluded law enforcement by stealing a truck and then escaping toward the mountains and woods just west of town.

The Montana attorney general, Austin Knudsen, said Mr. Brown could be using camping equipment and clothes he took from the truck, or could be hiding in old cabins or other buildings scattered throughout the forests.

Other high-profile killers in different kinds of crimes have eluded law enforcement for months or even years. A man accused of killing his three young daughters two months ago in Washington State remains at large. Eric Rudolph, who bombed the 1996 Olympics in Atlanta, was not captured until 2003.

Perhaps most notoriously, the Unabomber, Ted Kaczynski, spent nearly 20 years as one of the country’s most-wanted criminals until he was arrested at his remote cabin — in Montana.

Law-enforcement officials have provided few details about what precipitated the shooting at the Owl Bar in Anaconda, precisely how it unfolded or how the suspect was able to evade immediate capture.

Relatives of Mr. Brown have said he had a history of mental illness and delusions brought on by post-traumatic stress from his military service. Video footage from security cameras after the shooting shows Mr. Brown shirtless and in dark shorts, walking down a flight of stairs.

Renee Gursky, 28, who has known Mr. Brown for a decade, said he was “very much a survivalist” who could live in the wilderness.

State and county law enforcement officials did not respond to requests for an update on Thursday. A day earlier, they said in a social media post that the search was expanding, and that investigators were conducting interviews and chasing leads.

“Any critical information will be communicated to the community as soon as possible,” the Anaconda-Deer Lodge County Law Enforcement Center said in the post.

With official news scarce, many residents in this county of roughly 10,000 people have been trading rumors and secondhand information through text-message chains and local Facebook groups.

Some residents said they believed Mr. Brown was already dead, while others speculated about whether someone had given him a ride. Some wondered if he could be down an old mine shaft, or had slipped away into another section of forest.

“There’s so many rumors and so much speculation that you don’t know what actually is true,” said Lois Anderson, 65, who lives in the area where the search is centered. “Nobody knows but God.”

Ms. Anderson is jumpy these days, she said, but felt protected by the huge police presence in her neighborhood — the search has brought at least 250 officers to town — as well as her locked doors and firearms. “We have an arsenal here,” she said.

Michelle Lennon, 68, a former Marine who lives downtown, said she had spent the past few days mostly sitting at home, more out of sadness than fear.

“I just feel deflated,” she said. “It’s been a week, and we’re still waiting for this one guy.”