A grand jury has reached a decision on whether to indict Ferguson police officer Darren Wilson for killing Michael Brown, authorities confirmed Monday.

The Washington Post first reported the story.

The offices of the country prosecutor and Missouri Gov. Jay Nixon are preparing press conferences that are expected to be held later today, according to the Post. Nixon is on his way to St. Louis, his spokesman told reporters Monday.

The decision of the grand jury is not known at this time.

St. Louis Alderman Antonio French called for unity on Monday:

A spokesman confirmed Monday that Michael Brown's family had been notified, with a press conference scheduled for 4p.m. Missouri (CST) time.

Nixon is expected to appear for a media availability at 5:30pm Central Time with Department of Public Safety Director Dan Isom, St. Louis County Executive Charlie Dooley and St. Louis Francis Slay "calling for peace" and discussing preparations authorities have made for the reaction to the announcement.

The grand jury's decision is expected later Monday evening.

The Brown family called Monday for a period of silence to last four and a half minutes in honor of their son before any protests begin following the decision. Brown was left on the street for roughly four and a half hours after being shot.

"We are not here to be violent. We are here in memory of our son. We are here for protection of all children. We are here to support justice and equality for all people," the family said in a statement.

Wilson, 28, shot and killed the unarmed 18-year-old on Aug. 9, sparking weeks of protests in Ferguson and the surrounding St. Louis area. Wilson maintains that he was acting in self-defense.

Police and local authorities are preparing for possible violence if Wilson is not charged. President Obama has called on Ferguson to "keep protests peaceful," and Nixon has said "violence will not be tolerated."

Wilson married a fellow Ferguson police officer, Barbara Spradling, last month, the New York Times reported Monday. Wilson had reportedly been negotiating his resignation in the weeks prior to the grand jury decision, but no announcement has been made at this time.

This story was last updated at 4:52 p.m.