A man wearing a swastika armband was punched to the ground in downtown Seattle, after activists spread his photo across Twitter. The incident was caught on camera and uploaded online on Sunday.

The Seattle Police Department said they received reports of a man wearing a swastika armband and “instigating fights” late Sunday afternoon. When officers arrived on the scene, however, they found him on the ground. The man removed his armband and left without telling police what had happened.

Hours before, an anti-fascist Twitter account had shared a photo of a man riding the bus in Seattle with a Nazi armband on his right arm.

“Nazi s***head on D line headed to downtown #Seattle. Submitter said they were harassing a black man on the bus,” the account wrote, indicating that the photo had been submitted by a third party.

The photo spread quickly around anti-fascist social media accounts. Anti-fascists, or “Antifa,” as some of them are called, are a loosely organised group of activists who seek to fight racism, sexism, and other oppressive forces.

The original tweet was re-tweeted almost 60 times, and the photo was also shared on Reddit.

Shortly after it was posted, Seattle residents began to tweet out reports of a man matching the photo at a specific downtown intersection. According to Twitter reports, the man was “yelling at passerby” and “spewing racist vitriol”.

Less than an hour later, video emerged of a man with a swastika armband being punched by another man in a grey sweatshirt. In the video, the man falls to the ground and remains motionless as the man in the sweatshirt walks away.

“Night night,” the videographer says.

Seattle Police said no one at the scene contacted officers to report the incident.

While some Antifa Twitter accounts celebrated the incident, it is unclear whether the assailant in the video is anti-fascist-affiliated.

The Antifa are known to occasionally use violence when confronting neo-Nazi and other white supremacist groups. The practise gained mainstream attention last year, when self-proclaimed white nationalist Richard Spencer was punched on the street.

The movement returned to the national spotlight last month, when President Donald Trump accused the Antifa of being “very, very violent” at a white supremacist rally in Charlottesville, Virginia.

Violence on the streets of Charlottesville Show all 9 1 /9 Violence on the streets of Charlottesville Violence on the streets of Charlottesville Protesters clash and several are injured White nationalist demonstrators clash with counter demonstrators at the entrance to Lee Park in Charlottesville, Virginia. A state of emergency is declared, August 12 2017 Violence on the streets of Charlottesville Trump supporters at the protest A white nationalist demonstrator walks into Lee Park in Charlottesville, Va., Saturday, Aug. 12, 2017. Hundreds of people chanted, threw punches, hurled water bottles and unleashed chemical sprays on each other Saturday after violence erupted at a white nationalist rally in Virginia. AP Photo Violence on the streets of Charlottesville State police stand ready in riot gear Virginia State Police cordon off an area around the site where a car ran into a group of protesters after a white nationalist rally in Charlottesville, Virginia AP Photo Violence on the streets of Charlottesville Militia armed with assault rifles White nationalists, neo-Nazis and members of the 'alt-right' with body armor and combat weapons evacuate comrades who were pepper sprayed after the 'Unite the Right' rally was declared a unlawful gathering by Virginia State Police. Militia members marched through the city earlier in the day, armed with assault rifles. Getty Images Violence on the streets of Charlottesville Statue of Confederate General Robert E Lee The statue of Confederate General Robert E. Lee stands behind a crowd of hundreds of white nationalists, neo-Nazis and members of the 'alt-right' during the 'Unite the Right' rally 12 August 2017 in Charlottesville, Virginia. They are protesting the removal of the statue from Emancipation Park in the city. Getty Images Violence on the streets of Charlottesville Racial tensions sparked the violence White nationalists, neo-Nazis and members of the 'alt-right' exchange insults with counter-protesters as they attempt to guard the entrance to Lee Park during the 'Unite the Right' rally Getty Violence on the streets of Charlottesville A car plows through protesters A vehicle drives into a group of protesters demonstrating against a white nationalist rally in Charlottesville, Virginia. The incident resulted in multiple injuries, some life-threatening, and one death. AP Photo Violence on the streets of Charlottesville Rescue personnel help injured people after a car ran into a large group of protesters after an white nationalist rally in Charlottesville, Virginia AP Photo Violence on the streets of Charlottesville President Donald Trump speaks about the ongoing situation in Charlottesville, Virginia from his golf club in Bedminster, New Jersey. He spoke about "loyalty" and "healing wounds" left by decades of racism.

According to Antifa activists, however, the bulk of their work consists of researching and publicly identifying members of far-right movements – just as activists did in Seattle this weekend.

“Through research we can identify their leadership, their resources, their level of influence, and how best to deny them what they want,” an activist for the Atlanta Antifascists told The Independent last month.