A federal investigation will seek to judge whether the civil rights of Dontre Hamilton, the victim of police shootings, were abused.
On Monday, the Milwaukee County District Attorney dropped charges on Christopher Manney, the police officer responsible for the shootings, defining his actions as self-defense.
Hamilton's family said he was suffering from schizophrenia and has not been taking his medicine for some time, news outlets reported.
The prosecutors' decision not to charge Manney sparked protests in the city by religious and civil rights leaders on Monday. About 200 protesters demanded the review of the Hamilton's case.
The 18-year-old man was shot by police officer Darren Wilson in the city of Ferguson in August. The incident triggered mass protests across the country. A second wave of protests followed in November after a grand jury decision not to indict Wilson. Wilson quit his job and remains the subject of investigations.
