CLEVELAND — Officials are urging calm as they brace for expected protests after a grand jury voted not to indict a white Cleveland police officer for fatally shooting a 12-year-old black boy who was carrying what turned out to be a pellet gun.

Small groups of protesters gathered Monday outside the Cuyahoga County Justice Center and at the recreation center where Tamir Rice was shot by then-rookie patrolman Timothy Loehmann in November 2014. The size of those protests likely was reduced by a cold and steady rain that fell throughout the day.

County Prosecutor Tim McGinty announced that Loehmann and his field training officer wouldn’t be indicted because of “indisputable” evidence that Tamir was reaching for what officers thought was a real gun tucked in his waistband, and urged those who disagreed with the grand jury to protest peacefully.

“It is time for the community and all of us to start to heal,” McGinty said.

Cleveland Mayor Frank Jackson made a similar plea, as did Tamir’s family. Attorneys for the family condemned the grand jury’s decision but called on people to express themselves “peacefully and democratically.” Deputies set up metal barricades outside the Justice Center after McGinty’s news conference on Monday afternoon.