Police Officer Darren Wilson β€” the suburban St. Louis patrolman who killed unarmed teenager Michael Brown in early August – will not face criminal charges in the controversial shooting death, a grand jury has decided.

Wilson, who is white, became a national figure after he shot the black 18-year-old multiple times in broad daylight on a residential street. The grand jury deliberated for months and Ferguson was rocked by violent protests in the immediate aftermath of the shooting.

The decision was announced by prosecuting attorney Robert McCulloch, who discussed the lengthy deliberation period of the grand jury citing consideration of differing witness reports as a one reason for the unusually long session.

He laid out their sessions by the numbers: the jurors met 25 times and spent hundreds of hours poring over evidence.

McCulloch also expressed condolences for the Brown family. “My heart goes out to them. The family is going to have a loss forever,” he said.

On the whereabouts of Wilson, he said “I have no idea what his status us.” Last week several media outlets reported that Wilson was preparing to resign. Had he been indicted, Wilson would have been required to turn himself into authorities immediately.

Ahead of Monday’s announcement, Missouri Gov. Jay Nixon made a plea for peace.

“Our shared hope and expectation is that regardless of the decision, people on all sides show tolerance, mutual respect and restraint,” he said.

Meanwhile, officials in Clayton stepped up security measures erecting barricades around the courthouse to prepare for possible protests. A Yahoo News reporter spotted members of the National Guard arriving in military vehicles. Several Ferguson-area schools have announced they will be closed Tuesday.

β€œThe men and women of the National Guard also will be in the area to provide security at critical facilities like firehouses, police stations and utility substations, and offer logistical and transportation support as needed. This will free up law enforcement officers to do their jobs effectively,” Nixon said.

Demonstrators gathered ahead of the announcement holding signs, chanting and honking car horns.

The 12-member St. Louis County grand jury β€” which included one black man, two black women, six white men and three white women β€” has been hearing testimony since Aug. 20 to determine whether there was probable cause that Wilson had committed a crime.

Police experts have said officers generally have leeway to use lethal force if they reasonably fear they are in imminent danger.