LAKE COUNTY, ILLINOIS (NYTIMES) - He signed up to be a cadet in a programme for teenagers who aspire to be police officers. He filled his Facebook page with support for Blue Lives Matter.

He sat up front at a rally for US President Donald Trump in January, and posted images of it on TikTok.

And he chose to mark his 16th birthday by raising funds for a support group for the police called Humanising the Badge.

Now, at age 17, Kyle Rittenhouse is charged with homicide in a shooting that took place as counter-protesters sparred with demonstrators in Kenosha, Wisconsin.

He was there on Tuesday night (Aug 25) as demonstrators filled the streets to protest the shooting of Jacob Blake, a Black man, by a white police officer.

Rittenhouse, who is white, was carrying a military-style rifle and a medical kit, and stood amid a group of armed men who declared that they were protecting the area from fires and looting in protests that had turned destructive on earlier nights.

"People are getting injured and our job is to protect this business," Rittenhouse said early that evening in an interview with The Daily Caller, an online news and opinion site.

He had come to Kenosha from his home in Antioch, Illinois, 30 minutes away.

"Part of my job also is to protect people," he said.

"If someone is hurt, I'm running into harm's way. That's why I have my rifle; I've got to protect myself obviously. But I also have my med kit."

Hours later, two people were fatally shot, and a third wounded, as the groups - protesters and counter-protesters - clashed in a darkened, chaotic street.

Killed was Joseph Rosenbaum, 36, and Anthony Huber, 26, whose friends said he was protesting against the Blake shooting.

Rittenhouse, who faces six criminal counts, including first-degree reckless homicide, first-degree intentional homicide and attempted first-degree intentional homicide, was arrested at his home in Illinois on Wednesday morning, and was expected to appear in court there on Friday to determine whether he will be extradited to Wisconsin.

He was being held in a juvenile detention facility in Lake County, Illinois.

Joy Gossman, the Lake County public defender, who is representing him in the extradition case, declined to comment on whether he would fight the transfer.

A message left for Rittenhouse's family members went unanswered.

Video footage from the night provided many images of Rittenhouse, in an olive green T-shirt and a baseball cap with an American flag, sometimes marching alongside members of the Kenosha Guard, a right-wing militia, and other local armed groups.

Through the evening, he portrayed himself as having shifting roles - helper to injured people, cleaner of graffiti that had been left on walls, armed defender of property.

There are no overt links on Rittenhouse's social media accounts to militias or white supremacist groups who have dispatched armed men to protest events across the country.

Kevin Mathewson, 36, a former alderman in Kenosha, said he had organised the Kenosha Guard page on Facebook because he felt that the police were outnumbered by demonstrators and could not protect the city.

He did not know many of those who responded, he said in an interview, including Rittenhouse.

"I never met the guy, I have no idea who he is," he said.

Mathewson said he created the page during the George Floyd protests this year but got little traction; then last week, as protests were erupting in Kenosha, thousands of people responded to the call.

"Our city is under siege," he said. "There are bad people coming to Kenosha to do bad things."

During the evening, there were moments when the law enforcement officers seemed to treat Rittenhouse and some of the other armed men as allies, even as a city curfew began and the men stayed around.

In one video, Rittenhouse encountered officers who expressed appreciation for the efforts of the armed group and gave him bottled water.

In the background of the same video, another officer can be heard barking at protesters, telling them that they are violating the curfew.

In Wisconsin, an open-carry state, it is illegal for those under 18 years old to carry weapons openly in public, but Rittenhouse seemed to draw no scrutiny from the police for his gun.

At one point, after shots rang out and as emergency vehicles were racing through the confusing scene, Rittenhouse can be seen, weapon in full view, hands up, walking toward groups of officers - and appearing to go unnoticed by them.

Some who took part in the demonstrations against police misconduct saw the treatment Rittenhouse received is yet another example of the very racial inequities they had been out protesting.

"It's just a double standard," said Ja'Mal Green, a community organiser from Chicago who marched in Kenosha.

A Black person, he said, would never have been permitted to carry a weapon through the same scene without drawing scrutiny from the police.

"If they have an umbrella, if they have any object, they are deemed as armed," Green said.

"But this young white kid can come with a real gun, and he is treated way differently than any protester or any Black man in America."

David Beth, the Kenosha County sheriff, brushed aside questions about the interactions between law enforcement and Rittenhouse.

"Our deputies would toss water to anybody," he told reporters.

It is not clear whether Rittenhouse, who lives with his mother in an apartment complex in Antioch, is enrolled in school.

He had attended a nearby high school a few years ago, officials said, but the local school district said he was no longer enrolled.

Rittenhouse had two profiles on TikTok.

On one, he posted a picture from a rally for Trump in Iowa. On the other, he posted support for Blue Lives Matter, guns and Trump.

"Bruh, I'm just tryna be famous," he wrote in his bio summary on the account, which had attracted 26 followers.

One account features a video of him shooting a semi-automatic rifle, him and a friend at target practice, and Rittenhouse assembling a rifle.

That account also links to several Blue Lives Matter accounts, one with Confederate imagery.

Asked about Rittenhouse, Kellyanne Conway, the outgoing long-serving aide to Trump, told reporters, "We are not responsible for the private conduct of people who go to rallies."

Humanising the Badge, which works to improve relations between police departments and the community, said it was unaware of his fundraising effort, which anybody can organise on a Facebook page.

His mother, Wendy Rittenhouse, a nurse's aide, sought a protection order on behalf of her son in January 2017, accusing one of Rittenhouse's classmates of calling him "dumb" and "stupid" and threatening to hurt him, the Chicago Tribune said. She later dropped the case.

His mother posted pictures of him while he was enrolled in a cadet programme for aspiring firefighters in Antioch.

He had also served as a cadet in a public safety programme run by local police.

More recently, Rittenhouse had worked as a part-time lifeguard at a YMCA, but he was furloughed in March.

A manager at Culver's, a Midwest hamburger chain, said he had worked there briefly a year ago but it was "not a good fit."

His Facebook profile, deactivated soon after his arrest, overflowed with content lauding Blue Lives Matter for more than two years.

In November 2019, he had changed his Facebook profile picture to honour Samuel Jimenez, a Chicago police officer shot dead while on duty.

Facebook said that it had received several complaints about the Kenosha Guard page called Armed Citizens to Protect Our Lives and Property before Tuesday's rally but an initial review by general moderators had mistakenly left it up.

The complaints about the page should have been routed to a new team organised to evaluate "dangerous groups," the company said in a statement.

That team removed the page, with its more than 3,000 members, because it violated new rules to ban groups that celebrate violent acts or display weapons that they suggest will be used.

Rittenhouse was not among the members of the Facebook page and there was no indication on his page or in any post that he planned to ally himself with the group in Kenosha, the company said.

Daniel Miskinis, the police chief in Kenosha, attributed the violence to curfew violations.

"Persons who were out after the curfew became engaged in some type of disturbance, and persons were shot," Miskinis told a news conference.

"Everybody involved was out after the curfew. I'm not going to make a great deal of that, but the point is the curfew is in place to protect."

The killings provoked a strong reaction on social media.

Critics of the heavily armed presence of unofficial militia groups or members of the so-called "boogaloo" movement at protests across the country said such a tragic outcome was inevitable.

Supporters of Rittenhouse said he was being attacked by the mob and acted in legitimate self-defence.

Various efforts to raise money for a legal-defence fund, including one by a Three Percenter militia group, had collected more than $50,000 by Thursday before most appeared to have been removed.