MADISON, Wis. — Some of the Madison Police Department’s toughest critics peacefully protested in the hours after a prosecutor said he wouldn’t charge a white officer who killed an unarmed biracial man. But the city faced another test today as activists called for a widespread walkout.

After recent riots in cities where white officers have killed black men — including Ferguson, Missouri, and Baltimore — Dane County District Attorney Ismael Ozanne’s announcement Tuesday raised concerns that things could turn violent in Wisconsin’s capital city as well.

The Young, Gifted and Black Coalition, which called for the walkout, has staged multiple protests since Tony Robinson’s death on March 6. The group had demanded that Madison Officer Matt Kenny be fired and charged with homicide, but the rallies have been peaceful.

Ozanne, who is biracial but identifies himself as black, is Wisconsin’s first minority district attorney. He pointed out his racial heritage as he made the announcement, noting his black mother participated in the Freedom Summer, a black voter registration drive in Mississippi in 1964. He said he views Robinson’s death through that lens but made his decision based on the facts.

“I am concerned that recent violence around our nation is giving some in our community a justification for fear, hatred and violence,” Ozanne said as he wrapped up his announcement. “I am reminded that true and lasting change does not come from violence but from exercising our voices and our votes.”