Police officers in riot gear are seen outside a Walmart store during a protest in St. Louis Oct. 13, 2014. Reuters

It’s not just Ferguson and St. Louis that are preparing for demonstrations in the wake of a grand jury’s looming decision on whether to indict Darren Wilson, the white police officer who shot and killed unarmed black teenager Mike Brown in August. From Los Angeles to Boston, police departments have plans should large protests sweep the nation in the wake of a grand jury decision not to indict Wilson.

Lt. Michael McCarthy, a spokesman for the Boston Police Department, told the Associated Press the events in Ferguson are “definitely on our radar.”

"Commonsense tells you the timeline is getting close. We're just trying to prepare in case something does step off, so we are ready to go with it," McCarthy said.

While the grand jury is meeting in secret, leaks and news of the preparations have led protesters in Ferguson to say they believe Wilson will not be indicted. Robert McCulloch, the St. Louis County prosecutor, said a decision is expected to come down sometime in mid- to late November. The Root reported an announcement is "likely" Monday.

“We are getting prepared for war,” protester Ronardo Ward told KMOX, St. Louis. “And that’s just crazy.”

Los Angeles, the scene of the Rodney King riots in 1992, is one of the cities bracing for protesters.

“Naturally, we always pay attention,” LAPD spokesman Cmdr. Andrew Smith told the AP. “We saw what happened when there were protests over there and how oftentimes protests spill from one part of the country to another."

The New York Police Department said it’s prepared to handle any protests that might break out if Wilson isn’t indicted. The NYPD is "trained to move swiftly and handle events as they come up," spokesman Stephen Davis told the AP.

Riots rocked Ferguson shortly after Brown was shot and killed by Wilson and businesses were looted, including one that was burned down. The protests have since been peaceful.