A grand jury did not indict Ferguson, Mo., police officer Darren Wilson for any crimes related to the death of 18-year-old Michael Brown in August.

Wilson, who is white, shot and killed Brown, who was unarmed and black, in an Aug. 9 incident that has stoked anger and debate in Ferguson and beyond.

This story is developing, and we're updating this post to reflect the latest news.

Update at 9:24 p.m. ET: Grand Jury Does Not Indict Wilson

The grand jury found that "no probable cause exists" to file any indictments against Wilson, McCulloch said.

Earlier, the prosecutor said, "There is no question, of course, that Darren Wilson caused the death of Michael Brown." He then discussed areas of the law that might apply to the case, such as self-defense.

Update at 9:18 p.m. ET: First, An Overview

McCulloch began his news conference around 8:15 p.m. local time (9:15 p.m. ET), at a courthouse in Clayton, Mo., by expressing his sympathies for Brown's family, noting that they lost a loved one to violence.

He then ran through an overview of the events that have transpired since Wilson and Brown encountered one another on the street. And McCulloch stressed that all evidence in the case has been shared by local and federal agencies.

McCulloch went on to note challenges in the case, which he said ranged from the 24-hour news cycle to statements from witnesses that didn't match up — and some statements from witnesses that were later recanted.

But he stressed that nearly all witness interviews had been recorded and presented to the jury.

The jury's decision is coming out after weeks of anticipation and concern over how the Ferguson community might respond to the latest development in a case that has ignited racial tensions and pitted protesters and police against one another.

Hours earlier, Gov. Jay Nixon urged people on all sides of the issue to show "peace, respect, and restraint." One week ago, Nixon declared a state of emergency.