WELDON SPRING, Mo. (AP) — Missouri Gov. Jay Nixon said Tuesday that law enforcement officials have been working around the clock to make sure residents and businesses are kept safe once prosecutors announce whether a suburban St. Louis police officer will face charges for fatally shooting 18-year-old Michael Brown.

A grand jury is expected to decide later this month whether to indict Ferguson Officer Darren Wilson, who is white, in the Aug. 9 death of Brown, who was black and unarmed.

Weeks of protests followed the shooting and officials are trying to make sure things remain calm once the grand jury decision is announced. Nixon said looting and violence that marred mostly peaceful protests will not be tolerated.

“That ugliness was not representative of Missouri, and it cannot be repeated,” he said.

Nixon said that once the decision is announced, the state highway patrol will work with St. Louis County and city police as one unified command. The National Guard will also be available if needed.

During the protests after the shooting, police donned riot gear and patrolled in armored vehicles, drawing widespread criticism and raising questions about a program that supplies surplus military equipment to local police departments.

A small number of protesters in those first few days attacked squad cars, tossed molotov cocktails at officers and, in a few cases, shot guns in the direction of police and looted local businesses. Police responded with tear gas, smoke canisters and rubber bullets. On many nights, dozens were arrested.

St. Louis County police initially handled security, but criticism of their tactics prompted Nixon to put Highway Patrol Capt. Ron Johnson in charge. He and other police leaders said the response was necessary to protect officers, protesters and the public.

Some protest organizers fear police will be heavy-handed after the grand jury announcement.

Ashley Yates of St. Louis, co-creator of the group Millennial Activists United noted that the vast majority of protests have been peaceful and said Nixon should focus on addressing the systemic problems faced by minority communities, “not reactionary policing techniques.”

It isn’t just law enforcement getting ready for the announcement. Organizers of Yates’ group and other protesters gathered Tuesday for training that includes how to take notes and shoot video of police actions on the streets.

“There is a significant effort to make sure that people’s rights are protected and that there’s no violence on either side,” said Andy Stepanian, a spokesman for several protest groups.

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