An unarmed black man was fatally shot Friday night by a white police officer in Madison, Wis., touching off protests and chants of "Black lives matter" that continued into Saturday.

The police chief on Saturday called the incident a "perverse perfect storm" of details that for some appeared to fit the national narrative of officer-involved deaths of black men.

"I understand that," Police Chief Mike Koval said during a televised news conference, as he sought to reassure the community while asking for patience during the investigation.

Anthony Robinson, 19, was killed about 6:30 p.m. as police responded to reports of a disturbance, Koval said. Officers were told a man was jumping in and out of traffic and was suspected of battery before he ran into an apartment, he said. An officer forced his way inside, where Robinson struck the officer in the head, Koval said. The officer then fired his weapon.

The officer, identified as Matthew Kenny, 45, was placed on paid administrative leave, Koval said.

Robinson's mother, Andrea Irwin, declined comment Saturday. "All we want right now is to find out all the facts," said Jerome Flowers, a family friend.

The shooting is being investigated by the Wisconsin Department of Justice's Division of Criminal Investigation, the result of a 2014 state law requiring outside agencies to probe officer-involved deaths.

At least 150 people gathered outside the shooting scene Friday, and more protests were held Saturday.

Protests have been staged in Madison for months, many organized by Young, Gifted and Black, a group created after Michael Brown, 18, was fatally shot by police in Ferguson, Mo., in August. Said group cofounder Brandi Grayson: "We were a Ferguson waiting to happen."