Inside an apartment on a quiet suburban street near Lacey, Wash., on Thursday evening, Michael Forest Reinoehl fretted about his future. He talked about his children in a telephone call to a friend, wondering how to keep them safe should anything happen to him.
Outside, the F.B.I. kept watch. Moments later, U.S. Marshals and local law enforcement agents, with an arrest affidavit that accused Mr. Reinoehl of the shooting death last week of a far-right activist, raced toward the brick apartment building in two S.U.V.s.
Mr. Reinoehl, 48, a self-identified proponent of Antifa and a regular presence at the long-running protests against racial injustice in Portland, had seemed to confess to the killing in an interview with a journalist released hours earlier. He also said that he feared being killed in custody.
Soon after he emerged from the apartment, he was dead, shot and killed by law enforcement agents.
The U.S. Marshals Service said in a statement that Mr. Reinoehl was armed with a handgun when they arrived and threatened the lives of officers. But many details remain unknown, including whether Mr. Reinoehl fired any shots before or after several law enforcement officers opened fire.
Lt. Ray Brady of the Thurston County Sheriff’s Office said he was not aware of any video footage of the shooting, including from body cameras.
On Thursday evening, as Mr. Reinoehl lay dead in the street, police radios crackled with reports that shots had been fired. “Someone, the caller, hysterical saying someone opened fire and a female is screaming,” said one dispatcher, according to a transcript of the police transmissions.
Jashon Spencer, who lives nearby, said he went outside after hearing gunshots and saw a bloodied man in the street. A video he filmed showed a law enforcement officer attempting first aid.
Portland police had issued an arrest warrant for Mr. Reinoehl in the killing of Aaron J. Danielson, a supporter of a far-right group who was shot dead last Saturday after participating in a pro-Trump caravan and then taking to the streets of downtown Portland, where members of the caravan and their opponents clashed.
In an affidavit from Mr. Reinoehl’s arrest warrant, released Friday, authorities describe surveillance footage showing Mr. Reinoehl and Mr. Danielson first walking along a sidewalk, apparently without confrontation. Mr. Danielson was already carrying a can in one hand — possibly mace — and what appears to be an expandable baton in the other.
The footage shows Mr. Reinoehl turning into a parking garage, reached into a pouch or waistband, and waited for Mr. Danielson and a friend to pass, according to the documents. Authorities said Mr. Reinoehl followed the two men as they crossed the street in the seconds before the shooting
Both Mr. Reinoehl and Mr. Danielson had been stalwarts in the long-running street battles there pitting leftist demonstrators against various far-right groups.
In a news conference on Friday, Mr. Trump thanked the U.S. Marshals Service for their “strength” and “bravery,” saying that Mr. Reinoehl was killed after drawing a weapon when officers attempted to take him into custody.
Mr. Trump has deployed federal officers to the city and has threatened to do so again, while the city’s Democratic leaders have said the federal agents are aggravating the violence.
“You have this kind of culture where the right-wing vigilantes, though much smaller in number, are better armed and are calling for violence,” said Joseph Lowndes, a professor of political science at the University of Oregon. Whenever they appear, they are inevitably confronted by Antifa or other anti-fascist movements in Portland, and, he said, “you end up with this cycle of continuing confrontations.”
After the killing of George Floyd in police custody sparked protests and unrest across the country this summer, U.S. Attorney General William P. Barr formed a task force to investigate violent anti-government extremists. The F.B.I. has opened hundreds of investigations related to extremist activity, but has predominately charged those on the far right.
Yet in his public statements, Mr. Barr has pinned the violence on leftist groups and movements, particularly Antifa, and echoed assertions by President Trump that people on the left are inciting violent riots. On Friday, in a statement, he characterized Mr. Reinoehl as a “dangerous fugitive” and a “violent agitator.”
Friends and relatives described Mr. Reinoehl, a former professional snowboarder and father of two, as someone who had strongly held political beliefs. He relished his allegiance to Antifa, a loose alliance of activists, some of whom clashed with police during volatile street demonstrations throughout the summer.
“I am 100% ANTIFA all the way!” he wrote in a June Instagram post. His sister suggested the cause may have given him a sense of purpose, after his snowboarding career dwindled and he grew estranged from his family. “It made him feel like his existence meant something again,” she said.
Mr. Reinoehl found work as a construction contractor, according to his sister, who said escalating family conflicts brought a complete rupture three years ago.
“He was not very stable,” said the sister, an Oregon resident who declined to be identified by name because her family has received death threats.
Oregon State Police arrested Mr. Reinoehl in June after the authorities said he raced against his 17-year-old son on Interstate 84, with the Cadillac he was driving careening down the highway at 111 miles per hour. His 11-year-old daughter was in his car, according to the police report, and the police found a Glock pistol for which Reinoehl did not have a permit.
On July 5, during the protests, Mr. Reinoehl was charged with resisting arrest and the possession of a loaded firearm in a case that was later dropped.
Teal Lindseth, one of the main organizers of the Portland protests, called Mr. Reinoehl a “guardian angel” who had been by her side nearly every night. “He didn’t care who you were,” Ms. Lindseth said. “He would protect you no matter what.”
Tiffanie Wickwire, a friend who met him at protests earlier this summer, described him as a member of a security team that stood guard at the demonstrations.
Roughly an hour before his fatal encounter with law enforcement, Mr. Reinoehl called Ms. Wickwire and told her he was worried about the safety of his children and his family, she said.
“We were talking about his kids,” she said, “and what to do for them if anything happened to him.”
At 6:27 p.m., she said, she sent him a final text message: A screenshot of a Cash App fund-raiser she established for his children.
At 6:54 p.m., the first reports of shots fired were made, dispatch calls showed.
In an interview broadcast by Vice News on Thursday, Mr. Reinoehl appeared to admit to the Aug. 29 shooting death of Mr. Danielson, the right-wing protester in Portland, saying, “I had no choice.” Mr. Reinoehl said he had acted in self-defense, believing that he and a friend were about to be stabbed. “I could have sat there and watched them kill a friend of mine of color, but I wasn’t going to do that.”
Donovan Farley, the freelance journalist who conducted the interview, said that Mr. Reinoehl had expressed unease about surrendering to law enforcement and feared he would die in custody.
In the interview with Mr. Farley, Mr. Reinoehl appeared to acknowledge shooting Mr. Danielson — the owner of a moving business who would have turned 40 on Friday — after clashes between rival demonstrators.
When he was killed, Mr. Danielson was wearing a Patriot Prayer hat. Joey Gibson, the founder of Patriot Prayer, said that Mr. Danielson started attending the far-right group’s rallies regularly about three years ago. The group, based in the Portland area, has repeatedly engaged in physical conflicts with activists in the city, including a brawl that led to criminal charges against Mr. Gibson and others last year. The Southern Poverty Law Center has reported that some Patriot Prayer events have drawn white supremacists.
On Friday, Facebook said that it had deleted the pages linked to Patriot Prayer as part of its effort to remove “violent social militias” from its platform.
“He was not a monster, but what he did was still wrong,” said Mr. Reinoehl’s sister, noting that she did not condone the killing of either Mr. Danielson or her brother.
“I just declare it yet another tragedy in the growing list of tragedies,” she said. “The man that my brother killed should not have had to die. Things never should have gotten this out of control.”
Sarah Mervosh, Serge F. Kovaleski, Katie Benner and Thomas Fuller contributed reporting. Susan Beachy contributed research.