Missouri Governor Jay Nixon speaks before swearing in 16 members of the Ferguson Commission in St. Louis, Missouri in this November 18, 2014 file photo. [Photo/Agencies]

St. Louis County Prosecutor Bob McCulloch's office had said he expected a decision by mid-to-late November, but it was not ultimately not in his control. The 12-person grand jury deliberates in secret and sets its own schedule depending upon when the members are available.

Benjamin Crump, an attorney for Brown's family, said Sunday that they were frustrated the prosecutor did not charge Wilson himself or suggest a charge to grand jurors.

As it is, "you don't have any direction, you're just putting all the evidence out there and you're going to let them figure it out and they can make up their own minds," Crump said. "You know, it just boggles the mind why he thinks this is fair."

It's not uncommon for deliberations to take a while in complex cases when self-defense is alleged or when there are two widely conflicting versions, according to Cole County Prosecutor Mark Richardson, who is not involved in the Ferguson case.

Sunday would have been an opportune time to minimize disruptions from protests, since schools and governments are planning on only a partial holiday workweek, Washington University law professor Peter Joy said, but that Monday or Tuesday still would make sense.

During Sunday's church services, some pastors encouraged their flocks not to fret. The Rev. Freddy Clark of Shalom Church in Florissant told the mostly black interdenominational congregation that "justice will be served" no matter the decision goes, because God will take care of it.