MILWAUKEE — Following a night of violence that left half a dozen businesses in flames, the Milwaukee police chief expressed surprise at the level of unrest that erupted after the fatal shooting of a black man by a black officer.

“This was, quite frankly, unanticipated,” Police Chief Edward Flynn said Monday, two days after the worst of the rioting hit the Sherman Park neighborhood on the city’s economically depressed and largely black north side.

The city was calmer on Monday evening after two nights of unrest. Six arrests were made after some “heated confrontations” but there was no destruction of property or rioting, Flynn said. A 10 p.m. curfew for those under the age of 18 appeared to be honored with the aid of community leaders and parents, Milwaukee Mayor Tom Barrett said.

The chief’s statement raised questions about whether authorities could have taken steps to curb the violence, perhaps by sharing details of the shooting earlier, including the officer’s race or footage from his body camera.