Media outlets have identified the victim as 19-year-old Tony Robinson.

>> PHOTOS: Protests erupt in Wisconsin after police shoot, kill teen

Madison police say they encountered Robinson after receiving calls that a man had committed battery and was jumping in and out of traffic. Robinson, who was allegedly behind the disturbance, eventually ran into an apartment. The responding officer, later identified as Matt Kenny, reportedly then forced himself inside after hearing sounds of a disturbance and was struck in the head.

"In the context of mutual combat, in that sense, the officer then pulled his revolver and subsequently shot the subject," Madison Police Chief Mike Koval said.

Robinson's mother told WKOW she doesn't understand what led to the shooting.

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"My son has never been a violent person. Never. So to die in such a violent way, it baffles me," Andrea Irwin said.

Wisconsin law requires officer-involved shootings such as this one to be investigated by an outside agency, so Wisconsin's Department of Justice will be looking into the incident.

The protests following the shooting follow demonstrations in Ferguson, Missouri, and Staten Island, New York, from last year. In both those cases, unarmed black men were killed by police.

The Madison protests were organized by the Young, Gifted and Black coalition, a group that formed in the wake of the Ferguson shooting. Protesters on Saturday were marching from downtown Madison to the location where Robinson was killed.