Riverside County Sheriff Chad Bianco and a group of deputies were seen taking a knee alongside protesters during a demonstration.
Bianco called on the crowd to work with him to make a difference.
"We want you all to be here. We want you all to have this. We want your voices to be heard. We want to be heard together," he said.
Bianco added that he wants to see a change in the relationship between authorities and the community, and the only way that's going to happen is if everyone works together.
In the midst of massive, angry crowds, some Los Angeles Police Department officers also sought to make gestures of solidarity with protesters.
Thousands walked along Riverside streets in a massive show of support of the Black Lives Matter movement, which mostly remained peaceful.
However, as the night progressed, police used rubber bullets and pepper balls to push back a crowd amid exploding fireworks. Officials said a small amount of arrests were made for violating the countywide curfew put in place Monday, which has since expired.