The announcement by a St. Louis grand jury not to indict police officer Darren Wilson caps weeks of speculation and sparked protest action late Monday night.
A St. Louis county prosecutor will announce whether a grand jury has decided to indict the officer.
The policeman is accused of deliberately switching from rubber bullets to a live round and killing Nadim Nuwara, 17, at a protest in May.
Gunmen ordered non-Muslims off a bus Saturday and shot 28 dead. Muslim passengers were spared.
As tensions simmered in the St. Louis suburb over a case that has become a flashpoint for U.S. race relations, police in riot gear arrested three people in overnight protests.
The city erupted in cheers and flames after the Giants beat the Kansas City Royals.
A new video purports to show a marine surviving a sniper attack by a hair's breadth.
Cameron Tillman, 14, died after an alleged altercation with a police officer
Wilson is a 6-year police veteran with no disciplinary history, Police Chief Jackson said.
"Officers slammed me into a fountain soda machine because I was confused about which door they were asking me to walk out of," a Washington Post reporter wrote.
Crowds gathered Saturday and Sunday to protest the killing of an unarmed black teenager by police