FERGUSON, Mo. (AP) - A grand jury has decided not to indict Ferguson police officer Darren Wilson in the death of Michael Brown, the unarmed, black 18-year-old whose fatal shooting sparked weeks of sometimes-violent protests. St. Louis County Prosecuting Attorney Bob McCulloch announced the decision Monday evening. A grand jury of nine whites and three blacks had been meeting weekly since Aug. 20 to consider evidence. At least nine votes would have been required to indict Wilson. The Justice Department is conducting an investigation into possible civil rights violations that could result in federal charges. Brown's Aug. 9 death sparked more than a week of unrest that included angry clashes between police and protesters and led Missouri Gov. Jay Nixon to briefly summon the National Guard.