A Madison police officer fatally shot a man after authorities say the suspect stabbed him during a struggle Wednesday, sparking angry protests that spilled from the scene to the Wisconsin State Capitol as demonstrators demanded the officer be arrested and identified.

Cellphone video of the shooting spread rapidly across social media, capturing the sound of three gunshots as stunned bystanders watched from a busy intersection in one of the city’s most popular entertainment districts.

By nightfall, protesters had gathered where the man was shot, leaving flowers and candles before marching to the Capitol chanting, “Arrest the cops!” Demonstrators later took over the stage at a downtown summer concert series, prompting organizers to cancel the performance.

Black advocacy groups also condemned the shooting, with Urban Triage founder Brandi Grayson saying, “Another Black man is dead on a Madison street, and our community watched him die before we even knew his name.”

Police Chief John Patterson urged caution about drawing conclusions from the viral footage, saying it captured only one perspective of the encounter. He also offered his condolences to the family of the man, who was in his 30s but had not yet been publicly identified.

According to Patterson, officers responded to reports that someone was trying to get into parked vehicles in a neighborhood of restaurants, bars and homes less than two miles from the Capitol. The man fled on a bicycle through nearby backyards before officers confronted him on the street.

During the encounter, the man either fell from his bike or was pulled off it by officers, Patterson said. As they struggled, he allegedly produced a knife and stabbed one officer. Police later released a photograph of the knife they said was recovered at the scene.

An officer deployed a Taser, but it was ineffective, Patterson said. The officer who had been injured then fired his weapon. The man was taken to a hospital, where he died. The officer who fired the shots was described as a veteran of the department.

A second officer was also injured, although police have not said how. Two other officers were not hurt.

The Wisconsin Department of Criminal Investigation has taken over the investigation, as required in officer-involved shootings. All four officers involved have been placed on administrative leave under department policy.

The shooting unfolded on the same Madison street where white police officer Matt Kenny fatally shot Tony Robinson, who was biracial, in 2015. That case triggered weeks of protests after a prosecutor determined the shooting was legally justified and declined to file criminal charges.

Police have not released the race of either the officer who fired Wednesday’s shots or the man who was killed. However, Black advocacy groups said they believe the man was Black and called for transparency and accountability as the investigation moves forward.