St. Louis County Prosecuting Attorney Robert McCulloch said the grand jurors ruled that "no probable cause exists" to indict Wilson on any of the five possible charges that they were asked to consider.
Protesters have taken to the streets after the decision was announced. After using smoke, St. Louis County Police tweeted they had to turn to tear gas to disperse a crowd of protesters.
Elsewhere, there have been images of looting of a Ferguson liquor store, video of cars on fire (at least two of them are believed to be police cars), and photos of looting at Walgreen's and McDonald's. In St. Louis, hundreds of protesters gathered to block I-44.
The situation remains fluid so ABC News will be updating our live blog with the latest information as well as sharing photos from our reporters at the scene.