But what motivated Mr Rittenhouse to travel some 20 miles from his hometown in Antioch to another city to allegedly kill two people, and what do we know about the young man so far?
“I just killed somebody,” the 17-year-old is believed to have said, after allegedly shooting one of his victims in the head, and another in the chest, shortly before midnight on Tuesday evening.
Witnesses at the scene said Mr Rittenhouse walked past police armed with the weapon that he allegedly used to carry out the shootings - despite crowds calling for his arrest.
Mr Rittenhouse, according to his social media accounts, has an admiration for guns and the police.
Posts on Mr Rittenhouse’s Facebook account, which was deactivated on Wednesday following his first court appearance, show the teenager with a long-arm rifle, framed with the “Blue Lives Matter” logo.
The Blue Lives Matter movement was created in December 2014, after the homicides of NYPD officers Rafael Ramos and Wenjian Liu in Brooklyn.
In other Facebook posts, Mr Rittenhouse pays homage to law enforcement officers who died on duty. He also has a years-long association with local police cadet programmes, according to the Chicago Tribune.
Following Mr Rittenhouse’s arrest on Wednesday morning, video has emerged of the teenager in attendance at a Donald Trump rally in Iowa, back in January.
Footage from the event shows the teenager cheering for the president from the front row; he later posted a video from the rally on one of his two TikTok accounts.
When asked about Mr Rittenhouse’s attendance at the rally, senior White House aide Kellyanne Conway said: “We’re not responsible for the private conduct of people at our rallies any more than … all the crazy people who have been involved with the Obama/Biden campaigns or other things,” she said.
Mr Rittenhouse has been assigned a public defender ahead of his next court appearance. He is being held at Lake County juvenile detention facility pending a hearing on his potential extradition to Wisconsin, according to the sheriff’s office.
A reporter for The Daily Caller interviewed Mr Rittenhouse on camera before he is alleged to have carried out the killings. During the exchange, the reporter asked the 17-year-old what his purpose at the protest was.
“So people are getting injured and our job is to protect this business,” Mr Rittenhouse said. “And part of my job is to also help people. If there is somebody hurt, I’m running into harm’s way. That’s why I have my rifle because I need to protect myself, obviously. I also have my med kit.”
Kenosha County Sheriff David Beth confirmed to the Milwaukee Journal Sentinel earlier on Wednesday that armed people have been patrolling the streets of Kenosha in response to protesters looting, burning, and doing other damage to buildings and cars in the area. He could not say if the gunman from Tuesday was among them.
“They’re a militia,” Mr Beth said. “They’re like a vigilante group.”
Wisconsin’s lieutenant governor, Mandela Barnes, who is black, slammed the freedom of gunmen to walk the streets with rifles and face no repercussions.
“How many times across this country do you see armed gunmen, protesting, walking into state Capitols, and everybody just thinks it’s OK?” Mr Barnes said in an interview with Democracy Now!. “People treat that like it’s some kind of normal activity that people are walking around with assault rifles.”
Unrest following the shooting of Jacob Blake has quickly turned into a political flashpoint in one of the nation’s most important swing states. Ever since the killing of George Floyd earlier this summer, and the unrest that followed thereafter, one of the central tenets of the Trump campaign has been “law and order”.
Mr Trump has frequently attempted to portray Democrat-controlled cities as lawless, amid concerns that local leaders are not doing enough to quell unrest, which has often spilt over into violence.
The president and GOP are using this week’s Republican National Convention to shine a spotlight on violence and property damage that has resulted from some of the protests over racial injustice and police brutality this summer.
With violence in Wisconsin continuing, voters could be swayed by how local officials respond, in a state that Trump won by fewer than 23,000 votes in 2016; he was the first Republican to carry Kenosha County in 44 years.
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