Protesters took to the streets after a 19-year-old black man was shot and killed by a police officer in Madison on Friday night. Madison police have not identified the victim, but local ABC affiliate WKOW reports that his mother, Andrea Irwin, identified him as Tony Robinson. "My son has never been a violent person," Irwin said. "And to die in such a violent, violent way, it baffles me." Although Madison Police Chief Mike Koval said it was still unclear whether the victim had a gun, he said it didn’t look like that was the case. “Initial findings at the scene did not reflect a gun or anything of that nature that would have been used by the subject,” he said.

A crowd of demonstrators gathered at the scene after the shooting and chanted “Black lives matter,” reports the Wisconsin State Journal. Koval said that while it is “absolutely appropriate” for people to protest, he also urged “restraint” while the investigation moves forward.

The police chief said the officer was responding to a call about a man jumping into traffic. He followed the teenager to an apartment and forced his way inside after hearing a disturbance. “This same subject then assaulted my officer and in the context of mutual combat, the officer did draw his revolver and subsequently shot the subject,” Koval said. The officer apparently suffered a blow to the head and was taken to the hospital. Although he did not say for certain how many shots were fired, Koval said it was likely more than one.

Madison Mayor Paul Soglin called the killing “a tragedy beyond description,” according to the Associated Press. “I expect there will be a lot of anger and frustrations, particularly from friends.”