It was pitch black when the Border Patrol rolled as much as Raymond Mattia’s dwelling on a distant nook of the Tohono O’odham reservation in southern Arizona, investigating a report of gunshots.

Border brokers, smugglers and migrants have been a well-recognized sight within the tiny desert village a mile from the southern border the place the Mattia household had lived for many years. Mr. Mattia usually patrolled his property with a flashlight, his household mentioned. That night time in May, Mr. Mattia informed an older sister over the cellphone that he was heading exterior to satisfy the brokers, she mentioned.

But in a chaotic immediate in May, three Border Patrol brokers fatally shot Mr. Mattia as they stumbled on him within the desert, hitting him 9 instances, in keeping with an post-mortem. A Border Patrol report says he had tossed a sheathed machete towards an officer after which “abruptly extended his right arm.” His household mentioned he was unarmed and posed no menace.

His dying has touched off an outcry on the Tohono O’odham (pronounced Toh-HO-noh AW-tham) Nation, which lies alongside 62 miles of the southern border, and stirred up long-running resentments over the federal company’s presence on the Native American territory.

Tribal members go via border-security checkpoints stationed simply exterior the reservation on their option to Tucson, the closest massive metropolis, and say they’re frequently pulled over and questioned — encounters which have left a movie of worry and mistrust.

“I’m always on guard, always scared, nervous,” mentioned Vivian Manuel, who lives close to Mr. Mattia’s village. “They’ll harass you: What are you doing out here? Are you a tribal member?”

Yet Tohono O’odham leaders have referred to as the Border Patrol an ally in confronting drug and human smuggling on a 13,000-person reservation the scale of Connecticut. More than 600 migrants have died there over the previous decade making an attempt to cross the deserts and ragged mountains, in keeping with the migrant-aid group Humane Borders. The tribe says trafficking has broken its land and price the tribe hundreds of thousands in further work for its roughly 60-member police pressure.

John R. Modlin, the Border Patrol’s Tucson sector chief patrol agent who oversees the world, has described tribal partnerships as “essential to our national security mission.” The Border Patrol’s social-media feed is stuffed with posts displaying brokers serving to the tribe combat wildfires, planting saguaro cactuses and stopping traffickers who cross the reservation with migrants packed into automobile trunks.

The Border Patrol launched a prolonged account of Mr. Mattia’s killing in addition to body-camera footage. An investigation is being performed by the F.B.I. and the Tohono O’odham Police Department. The businesses declined to debate the capturing, citing the investigation.

Ned Norris Jr., the Tohono O’odham chairman, mentioned in a press release that he had “serious concerns” about Mr. Mattia’s killing however was reserving judgment. He didn’t reply to a request for remark.

News of the capturing has rippled via different tribes close to the border, forcing some leaders to grapple with their very own combined emotions concerning the federal presence round their lands.

“We always worry about both sides, whether it’s the cartels or some of the agents who man these border patrols who have guns,” mentioned Peter Yucupicio, chairman of the Pascua Yaqui Tribe, whose headquarters are in Tucson. “You start wondering as a tribal member: If I do something wrong, am I going to get all shot up.”

United States Customs and Border Protection, the umbrella company of the Border Patrol, has reported a median of roughly 15 use-of-force incidents involving weapons every year since 2020. Many of these occurred after car pursuits or different makes an attempt to apprehend smugglers and migrants, in keeping with news stories and accounts from the company.

But the capturing of a tribal member on tribal lands units this case aside.

The Tohono O’odham, whose identify means “desert people,” ranged throughout the Sonoran desert for hundreds of years earlier than there was a border, following seasonal water flows, searching deer and harvesting fruit from cactuses, in keeping with tribal histories.

Their conventional lands have been cut up in two when the 1853 Gadsden Purchase set the boundary between the United States and Mexico.

In the a long time that adopted, the Border Patrol has constructed surveillance towers and substations on the reservation, and its white pickups roam highways and sandy again roads. The tribe has about 33,000 members, most of whom stay off the reservation.

Many attempt to honor their cross-border heritage by visiting household and graveyards on the Mexican aspect, or by crossing to carry spiritual ceremonies or are likely to ranching inventory.

They should current tribal identification playing cards to go into the United States at devoted gates, and tribal leaders say that Tohono O’odham making an attempt to journey forwards and backwards have been detained and had ceremonial objects like pine leaves and candy grass confiscated.

The tribe resisted the Trump administration’s marketing campaign to construct a border wall as an infringement on its freedoms, so as an alternative of a 30-foot-high line of metal columns, the border is marked largely by X-shaped car limitations and a gap-toothed bollard fence.

Some within the tribe mentioned they weren’t bothered by the Border Patrol’s presence.

But others mentioned a historical past of run-ins had left them leery, similar to a 2014 incident by which a Border Patrol agent shot and wounded two joyriding Tohono O’odham males after they by chance clipped the agent’s parked pickup truck one moonless night time. A federal decide later discovered the capturing was not justified and awarded the boys greater than $250,000.

“They need to look at us as people and not like we’re all criminals,” mentioned Angelita Reino Ramon, whose 18-year-old son was fatally struck by a Border Patrol truck 20 years in the past in what a decide later referred to as an unavoidable accident. “They need to have more respect.”

The actual circumstances that led to Mr. Mattia’s dying the night time of May 18 are nonetheless hazy.

The name started round 9 p.m. when tribal police requested the Border Patrol for assist responding to a report of two gunshots heard in Mr. Mattia’s village, Menagers Dam, in keeping with a press release from Customs and Border Protection.

In radio recordings and body-camera movies, dispatchers and officers mentioned it was unclear the place the photographs had come from. Before heading out, they cautioned that somebody within the space might need a rifle.

At 9:37 p.m., the brokers and not less than one tribal police officer pulled as much as the village and unfold out round Mr. Mattia’s darkish cinder-block home. There was only a sliver of moon that night time, and within the video, their flashlights barely penetrate a ghostly panorama of out of doors furnishings, creosote bushes and cactuses.

“I thought somebody just ran this way,” an agent mentioned, jogging into the comb.

The tribal officer and brokers discovered Mr. Mattia close to a picket construction about 100 yards away from his home. They ordered him to come back out along with his arms up. “I am,” he mentioned and tossed a sheathed machete via the air, which landed close to an officer’s ft.

Several officers began yelling, ordering Mr. Mattia to take his arms out of his pocket and get on the bottom. Seconds later, they fired the deadly burst of photographs.

As the brokers handcuffed and flipped Mr. Mattia onto his again, one yelled out to “secure the gun” that they mentioned was beneath his limp physique. Instead, they discovered a cellphone and its case.

The case is already testing parallel efforts by the Biden administration each to strengthen ties and belief with tribes, and overhaul how Border Patrol shootings are investigated.

Last 12 months, the administration disbanded secretive “critical incident teams” throughout the Border Patrol that had been criticized for successfully permitting the group to analyze itself after occasions like Mr. Mattia’s killing. The administration additionally ordered federal law-enforcement businesses, together with the Border Patrol, to put on physique cameras and promptly launch footage after shootings.

The administration’s Covid rescue package deal contained $1.75 billion for American Indians and Alaska Natives, and the administration additionally created a Homeland Security advisory council centered on tribal points. Its 15 members embody the Tohono O’odham tribal chairman.

Mr. Mattia’s relations say they’ve little religion within the investigations, and have struggled to get solutions from each the tribal authorities and the Border Patrol.

Frustrated, a dozen relations and supporters placed on matching purple T-shirts bearing Mr. Mattia’s picture and held a small protest throughout the freeway from a Border Patrol station, simply exterior the reservation boundaries.

They burned sprigs of creosote bushes and took turns waving posters that referred to as for justice and huddling underneath umbrellas to get out of the solar.

Mr. Mattia’s household described him as a ceremonial chief of their neighborhood who made wooden carvings and beloved searching deer. His sister, Annette Mattia, mentioned the household had lived in the identical space for generations, however that the capturing had shattered their sense of dwelling.

“We don’t even want to be here anymore,” she mentioned.