Tapping on his cellphone with a sense of purpose, Kevin Mathewson, a former wedding photographer and onetime city alderman in Kenosha, Wis., did not slow down to fix his typos as he dashed off an online appeal to his neighbors. It was time, he wrote on Facebook in late August, to “take up arms to defend out City tonight from the evil thugs.”
One day earlier, hundreds of residents had poured onto the streets of Kenosha to protest the police shooting of 29-year-old Jacob Blake. Disturbed by the sight of buildings in flames when he drove downtown, Mr. Mathewson decided it was time for people to arm themselves to protect their houses and businesses.
To his surprise, some 4,000 people responded on Facebook. Within minutes, the Kenosha Guard had sprung to life.
His call to arms — along with similar calls from others inside and outside the state — propelled civilians bearing military-style rifles onto the streets, where late that night a gunman scuffling with protesters shot three of them, two fatally. The Kenosha Guard then evaporated just as quickly as it arose.
Long a divisive figure in Kenosha, Mr. Mathewson, 36, who sprinkles his sentences with “Jeez!” and describes himself as “chunky,” does not fit the typical profile of a rifle-toting watchdog, although he said he supported President Trump on Second Amendment grounds. The rise and fall of his Kenosha Guard reflects the current spirit of vigilantism surfacing across the country.
Organizations that openly display weapons have existed for decades, with certain hot-button issues like immigration or Second Amendment rights inspiring people who think the Constitution is under threat. Anti-immigrant and Islamophobic sentiments are rife, and some militant groups, like the Oath Keepers or the Three Percenters, train together under established hierarchies. Ever since the 2017 white nationalist march in Charlottesville, Va., armed groups have become fixtures at demonstrations around the country, although membership numbers remain opaque.
With the approaching election ratcheting up tensions in recent months, armed groups that assembled via a few clicks on the keyboard have become both more visible and more widespread. Some especially violent groups were rooted in longstanding anti-government extremism, like the 14 men charged with various crimes in Michigan this month. They included six accused by the F.B.I. of plotting to kidnap Gov. Gretchen Whitmer, whom the suspects had labeled a “tyrant” — framing their grievances in the vocabulary of the American Revolution.
Starting in April, demonstrations against coronavirus lockdowns prompted makeshift vigilante groups to move offline and into the real world. That trickle become a torrent amid the nationwide protests after the police killing of George Floyd in Minneapolis — with some armed groups claiming to protect the protesters while others sought to check them.
When President Trump was asked at last month’s presidential debate about activity by right-wing extremists, including the violence in Kenosha, he declined to outright condemn such groups, and told one far-right group to “stand back and stand by.”
Experts who study violent groups say that many are technically not militias — they are too unstructured and do not undertake basic steps like training together. They are usually just a fraternity with a shared goal, like the groups in Oregon that patrolled back roads amid wildfires, hunting mostly imagined looters or arsonists.
In Kenosha, police officers were caught on video expressing appreciation to the gunmen and handing them bottles of water, prompting criticism that law enforcement officers encouraged the armed groups.
But soon after, the sheriff tried to distance his department. “Part of the problem with this group is they create confrontation,” David Beth, the Kenosha County sheriff, told reporters at a news conference. Asked later about any investigation, the Sheriff’s Department said it had not referred any cases linked to the Kenosha Guard for prosecution, and the Police Department did not respond.
Mr. Mathewson first tried to muster the Kenosha Guard in June after the city had small protests because of Mr. Floyd’s death in Minnesota. A little more than 60 people responded.
Then, on Aug. 23, video emerged that showed a Kenosha police officer firing seven times toward Mr. Blake’s back.
When protests disintegrated into property destruction, Mr. Mathewson said, he thought law enforcement was overwhelmed.
After two nights of demonstrations, he posted an event on Facebook called “Armed Civilians to Protect our Lives and Property.” He named himself commander of the Kenosha Guard and added an open letter to the police telling them not to interfere.
Several hundred people volunteered to participate and around 4,000 expressed approval. His call to arms spread to other platforms, like Reddit. Infowars, the website that traffics in conspiracy theories, amplified it, as did local right-wing radio stations.
Mr. Mathewson said he had long believed that Americans should protect themselves. “You cannot rely on the government or the police to protect you,” he said.
Before forming the Kenosha Guard, he had seen reports focused on armed groups deploying in Minneapolis and Portland, Ore. “It was so far from me that it did not seem real,” he said. “When it happens in your own backyard, your own city, it is like, ‘Jeez, what can I do?’”
“I am pro-Second Amendment, but I am not a right-wing nut job,” he added.
Posts on Facebook amplified the sense of siege in Kenosha by spreading false rumors that murderous gangs from Milwaukee, Minneapolis and Chicago were coming to ransack the city of 100,000 people.
Jennifer Rusch, 47, a hair stylist, clicked on Mr. Mathewson’s webpage to find armed men to protect her business. “Facebook had a lot to do with making everybody hysterical,” she said. “Now we know 99 percent of it was lies.”
People messaged Mr. Mathewson from around Wisconsin and other states, asking where to deploy. He could not handle the avalanche of responses flooding his cellphone, he said.
“People thought we had some kind of command staff or a structure but it was really just a general call to arms” meant mostly for his neighbors, Mr. Mathewson said.
That night, Mr. Mathewson stuck to the entrance of his subdivision, WhiteCaps, at least seven miles from the city center. Pictures show him wearing a baggy red Chuck Norris T-shirt and knee-length camouflage shorts, with a rifle slung over his chest. He passed the early evening sitting outside on a lawn chair with some armed neighbors, then went to bed early.
While he slept, downtown Kenosha boiled over.
Witnesses blamed the violent disarray partly on the fact that many gunmen downtown were strangers to one another, with some on rooftops acting as spotters to call in reinforcements and no one in command.
To Raymond K. Roberts, a real estate investor and six-year Army veteran who monitored the vigilantes, the parade of jacked-up pickup trucks filled with armed men resembled Afghanistan.
Mr. Roberts noticed that law enforcement officers largely ignored the men.
The gunmen never seemed to realize that all the combat weaponry made Black residents like himself particularly uneasy, Mr. Roberts said, and that the community would have preferred to protect itself. “They just had this assumption that we don’t exist,” he said.
As tensions surged with protesters and armed enforcers tussling, authorities say that Kyle Rittenhouse, a 17-year-old from nearby Illinois, opened fire with a military-style semiautomatic rifle, killing two protesters and seriously wounding a third. He faces homicide charges and has become a poster boy for the far right.
Mr. Mathewson remains unsure which armed men downtown responded to his call and he denied having any contact with Mr. Rittenhouse.
Longtime Kenosha residents said they were conflicted over Mr. Mathewson, with his behavior angering some and others praising his many years as an independent watchdog.
Fans noted that he had chased down surveillance videos that exposed bad police behavior and, before leaving his alderman post in 2017, pushed for police body cameras that have still not been bought. But critics said he had turned himself into a nuisance by transforming political differences into personal vendettas.
Angie Aker, a community activist, initiated a criminal complaint against him as an accessory to the protest deaths. “I think he invited people in who were looking for a reason to shoot,” she said. There is also a federal lawsuit that names Mr. Mathewson, along with Mr. Rittenhouse and Facebook, among others, for depriving the four plaintiffs of their civil rights; one is the partner of a victim and the three others allege that armed men assaulted them.
Mr. Mathewson said what he did was covered by free speech.
After the shootings, Facebook banned Mr. Mathewson for life, removing his personal and professional pages. He said he lost 13 years of photo archives, including videos of his daughter and son taking their first steps and a memorial page for his mother.
Mr. Mathewson said that for now he had no plans to revive the Kenosha Guard. His wife has had enough of the spotlight, he said, with his phone ringing constantly.
“I am getting love and hate from all over the country,” he said.