After hearing testimony for nearly three months in the death of Michael Brown, the 18-year-old unarmed African-American who was shot by Officer Darren Wilson on a Ferguson, Mo., street on Aug. 9, a St. Louis County grand jury is nearing a decision on whether to bring criminal charges.

Routinely, grand juries are virtual rubber stamps for prosecutors, approving the proposed indictments after hearing from a few witnesses and getting the bare outlines of the incriminating evidence.

But the Ferguson case, laden with incendiary emotions, is anything but routine, and the grand jury proceeding has been highly unusual.

The St. Louis County prosecuting attorney, Robert P. McCulloch, said from the outset that his office would be “presenting absolutely everything” to the grand jury, including eyewitness accounts of the fatal altercation and forensic conclusions that might be diametrically opposed. The proceedings have been prolonged and exhaustive, in some ways more resembling a criminal trial than a normal grand jury hearing and shifting heavy responsibility onto the 12 jurors, nine white and three black, on the panel.