St. Louis, November 18 (RHC)-- The governor of the U.S. state of Missouri declared a state of emergency on Monday and put the National Guard on alert ahead of a grand jury decision on the murder of African-American teenager Michael Brown.

The move came as protests over the police killing of unarmed Black teenager Michael Brown continue. Governor Jay Nixon said in a statement the measure is in anticipation of more unrest as a grand jury deliberates about bringing criminal charges against the white police officer who killed Brown in the town of Ferguson on August 9th.

The jury's ruling will determine whether Darren Wilson is charged with a crime and faces a trial. Many in the predominantly Black St. Louis suburb expect another wave of violent protests if no charges are brought against the officer or if the jury decides that no criminal act was committed by Wilson.

The governor also puts the St. Louis County Police Department, rather than police in Ferguson in charge of policing protests. Meanwhile, several dozen people held a demonstration in Clayton, where the grand jury is deliberating.

Brown's family and activists want prosecutors to charge Wilson with murder. According to a poll by The New York Times/CBS News, the majority of African-Americans have lost confidence in the justice system following the killing. The poll found about six in 10 Blacks said they had little to no confidence the investigation into Brown's shooting would be handled fairly.