Michael Forest Reinoehl, 48, died in Lacey, Wash., outside Seattle, during an operation by a federal fugitive task force.
The suspect was shot by law enforcement after drawing a gun on officers, The Associated Press reported.
The task force was composed of personnel from the FBI and the U.S. Marshals Service.
In a statement early Friday, the Marshals Service said the task force was acting on a murder warrant for Reinoehl obtained by Portland police.
"Initial reports indicate the suspect produced a firearm, threatening the lives of law enforcement officers," the statement read. "Task force members responded to the threat and struck the suspect who was pronounced dead at the scene."
Portland police had obtained the warrant for Reinoehl earlier in the day, amid their investigation into the Aug. 29 fatal shooting of Aaron “Jay” Danielson, 39, on a night in which supporters of President Trump clashed with backers of the Black Lives Matter movement in Oregon’s largest city.
Earlier Thursday, Reinoehl was quoted in an interview on the Vice website, claiming he was a marked man.
“They’re out hunting me,” Reinoehl, 48, a father of two, told an independent reporter in the interview posted Thursday by Vice.
“There’s nightly posts of the hunt and where they’re going to be hunting. They made a post saying the deer are going to feel lucky this year because it’s open season on Michael right now.”
Reinoehl told journalist Donovan Farley in the interview that he had no regrets about firing his weapon last weekend.
“I was confident that I did not hit anyone innocent and I made my exit,” he said.
Prior to Thursday's law enforcement action, the assertion that Reinoehl was a person of interest in the Danielson shooting came from Reinoehl’s sister and an anonymous law enforcement source, both of whom spoke this week with The Wall Street Journal.
Reinoehl was a frequent participant in the nightly protests in Portland that have been occuring since the May 25 death of George Floyd in police custody in Minneapolis -- and reportedly was involved in several confrontations.
Among them: In July, Reinoehl suffered a gunshot wound while trying to wrestle a gun away from a stranger, and was also cited for allegedly carrying a loaded gun to a protest on July 5, The Oregonian reported.
On July 26 he was wounded in a brawl in a downtown Portland park.
On the evening of the Danielson shooting, Reinoehl said in the Vice interview, he tried to assist a friend who was being confronted by Trump supporters. He said one man threatened him and his friend with a knife.
"Had I stepped forward, he would have maced or stabbed me," Reinoehl claimed.
Videos shot by bystanders appear to show a man resembling Reinoehl firing two shots at Danielson and then walking away, the Vice report said.
'ANTIFA all the way'
In an online post from June 16, Reinoehl described himself as being "100 % ANTIFA all the way!"
“Every Revolution needs people that are willing and ready to fight,” he allegedly wrote, according to The Oregonian. “There are so many of us protesters that are just protesting without a clue of where that will lead. That’s just the beginning that’s that where the fight starts. If that’s as far as you can take it thank you for your participation but please stand aside and support the ones that are willing to fight. I am 100 % ANTIFA all the way! I am willing to fight for my brothers and sisters! ... We do not want violence but we will not run from it either! ... Today’s protesters and antifa are my brothers in arms.”
Earlier this week, a friend of Danielson's claimed that Danielson was "executed" and "hunted down" for his conservative views.
Chandler Pappas told The Common Sense Converstive he was with Danielson as part the Patriot Prayer group in downtown Portland on Saturday when counterprotesters arrived in the area. The two groups quickly clashed in tense confrontations that escalated into violence.
"We have a First Amendment in the country," Pappas told the news site. "And for whatever reason, there seems to be this opposition that thinks we can't do that. They have been attacking us for years. Really for decades in the grand scheme of things but very heavily in Portland."
Pappas claimed he and Danielson were targeted because they were wearing Patriot Prayer caps.
"It takes a second for you to process everything that happened. 'Did he just shoot at me?'" Pappas said while standing in front of a Blue Lives Matter flag. "I'm OK. I turn over and Jay's dead because he believed something different. Jay's not a racist, a xenophobe or whatever. He's not an 'ist' or 'ism.'"
"They executed my parter," he said. "They hunted him down."
Around the same time Thursday night that news reports were breaking about Reinoehl being killed, President Trump tweeted his frustration that police hadn't yet made an arrest in the death of Danielson.
"Why aren't the Portland Police ARRESTING the cold blooded killer of Aaron "Jay" Danielson," the president wrote. "Do your job, and do it fast. Everybody knows who this thug is. No wonder Portland is going to hell!"
Fox News' Louis Casiano and The Associated Press contributed to this report.