"Stand up! Fight back!" the protesters shouted, with some brandishing signs reading, "Black Lives Matter."
The protest appeared to be well under control; the video shows police lights flashing nearby. But one driver in a white SUV got fed up with the chanting and took off into the crowd.
A video of the moment, posted below, shows a large rectangular object hit the window of the SUV, followed by a loud noise like glass breaking. The video continues as the driver stops briefly, then speeds away.
No one appears to have been injured in the fracas.
KMOV reports that, prior to the incident, the driver briefly spoke to the protesters before taking off into the crowd.
At one point during the protest, some of the demonstrators blocked the road. A man in a white SUV and some of the protesters talked for five minutes about the protest and why they were blocking the road.
During their conversation, an officer approached the driver and said something to him, the driver was then heard on video stating “Nah, I want in this” and the officer walked away while the protester and driver continued their conversation.
Kirkwood police did not return our call seeking comment this morning. We'll update this post if we hear back.