A Ferguson, Missouri, police officer was critically injured outside the city’s police station during protests on the 10th anniversary of the fatal shooting of Michael Brown, police said on Saturday.

The Ferguson police chief, Troy Doyle, said Officer Travis Brown suffered a severe brain injury on Friday after being knocked to the ground. “He is in an area hospital right now fighting for his life,” Doyle said.

Two other officers also were hurt, one sustaining an ankle injury and another an abrasion. Both were treated at the scene.

The team of officers went out to make arrests on Friday for destruction of property at the police station, where protesters gathered to remember Michael Brown, the unarmed Black 18-year-old who was killed by Darren Wilson, a white police officer in 2014 – a pivotal moment in the national Black Lives Matter movement.

On Saturday, one of the suspects was charged with assault of a special victim, resisting arrest and property damage. He was ordered to be held on $500,000 cash only bond.

Doyle said that for the majority of the night, the protesters were peaceful. He said police allowed them to block the street outside the station, posting a squad car on each end, so they would not be hit by vehicles.

Police also did not intervene when the protesters began shaking the fence outside the station. But he said that when they broke a section of fencing, he sent out the arrest team. The suspect who charged at Travis Brown knocked him backward with his shoulder, and the officer hit his head as he tumbled to the ground, Doyle said.

Court records said the suspect then kept running and kicked two officers who tried to arrest him, leaving them with scratches and bruises.

Doyle said Travis Brown, who is Black, started with the department in January and previously worked for the St Louis county police.

He is part of a wave of Black officers hired into the department since 2014. Back then, there were just three Black officers in the department, but Black officers now make up more than half of the police force, Doyle said.

“He wanted to be part of the change,” Doyle said. “He wanted to make an impact in our community. He’s the type of officer that we want in our community. And what happens? He gets assaulted. I had to look his mother in the eye and tell her what happened to her son. I’m never going to do that again, I promise you that.”

St Louis county prosecutor Wesley Bell, who visited the hospital to meet with the officer’s family, said others also would be charged.

“I always talk about you know the toughest part of this job is when we have a family that’s lost a loved one that we can’t bring justice to. And I’ve got to tweak that. The toughest thing I’ve had to do is talk and console with a mother who doesn’t know if her child is doing to make it. And for what?”

It was not clear who organized Friday’s protests. One activist who attended an event earlier in the day at a memorial to Michael Brown, and another who organized previous protests, did not immediately respond to calls and text messages from The Associated Press seeking comment.

Michael Brown’s death turned Ferguson into the focal point of a national reckoning with the historically tense relationship between US law enforcement and Black people.

In 2015, an investigation by the US justice department also found no grounds to prosecute Wilson. But the report gave a scathing indictment of the police department – raising significant concerns about how officers treated Black residents, and about a court system that created a cycle of debt for many residents.