A white Wisconsin police officer won't face criminal charges for fatally shooting an unarmed 19-year-old biracial man whom witnesses say was acting erratically and had assaulted two people, a prosecutor announced Tuesday.

Dane County District Attorney Ismael Ozanne, who is biracial but identifies as black, said he won't file charges against Madison Officer Matt Kenny in the death of Tony Robinson. Kenny shot Robinson on March 6 in an apartment house near the state Capitol building.

Police said Kenny was responding to calls that Robinson was running in and out of traffic and had assaulted two people. They said Robinson attacked the officer after he entered the apartment house.

The city's black community mounted daily rallies for a week after the shooting. The protests were peaceful, although demonstrators demanded Kenny be fired and charged with homicide.

The state Department of Justice investigated the shooting under a state law that requires outside agencies to lead probes into officer-involved deaths. The state agency handed over its findings to Ozanne on March 27.

The shooting was another in a series of police confrontations that have ignited racial tension across the nation in the past year, and the second such officer-involved death in Wisconsin during the period. Milwaukee Police Officer Christopher Manney, who is white, fatally shot 31-year-old Dontre Hamilton, who was black, during a scuffle in a downtown park in April 2014.

Manney also wasn't charged. The local district attorney, who is white, said Manney acted in self-defense, which sparked days of peaceful protests in the state's largest city. But Manney was fired for what Milwaukee Police Chief Ed Flynn said was improperly frisking Hamilton in the lead-up to the shooting. A police commission upheld the dismissal.

Most recently in Baltimore, riots erupted after the funeral for Freddie Gray, a black man who suffered a fatal spinal injury while in police custody. Other high-profile cases of officers killing unarmed black residents include the deaths of Michael Brown in Ferguson, Missouri; Eric Garner in New York City; and Walter Scott in North Charleston, South Carolina.

Six officers involved in Gray's death have been charged, as has the officer who killed Scott. Grand juries declined to charge the officers involved in Brown's and Garner's deaths.