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 whites and three African-Americans, on the panel.

"The grand jury is probably going to hear more about this case than any other grand jury has heard about any other case in living memory," said Peter A. Joy, a professor at the Washington University Law School in St. Louis, of the extended and varied testimony.

After instruction in the range of possible criminal charges, from intentional murder to criminally negligent manslaughter, and after hearing the legal grounds for an officer’s use of deadly force, the grand jury will have to make some crucial judgments.

For example, did the officer "reasonably believe" that he or others were in serious jeopardy? Will at least nine of the 12 jurors agree that there is "probable cause" to bring a criminal charge?

"The prosecutors appear to be giving the grand jury the ability to decide for themselves," said Ric Simmons, a former prosecutor and professor of criminal law at the Moritz College of Law at Ohio State University. They may hope that the decision will have more credibility with an already inflamed public because, he said, "it will be based on the community’s voice, not the prosecutor’s decision."

"I think it’s a good thing," Simmons added. "It’s the original reason why we want to have grand juries."

But Brown’s family and their supporters have expressed deep suspicion about the drawn-out proceedings, arguing that Wilson should have been indicted months ago.

"It seems to me that there is a secret trial that’s taking place," said Anthony D. Gray, a lawyer for the Brown family. "This notion that all of the evidence needs to be presented in order to determine probable cause is faulty, in my opinion."

In another highly unusual step, Wilson himself testified before the grand jury in September, for four hours and, per court rules, without a defense lawyer present.

"Most defense lawyers would not let their client go anywhere near the grand jury," said Katherine Goldwasser, a former federal prosecutor and a law professor at Washington University. But in this case, she surmised, Wilson may have wanted to tell the jurors directly why he had felt justified in repeatedly shooting Brown, and why he believes he acted within the guidelines for deadly force.

Instead of recommending a charge, as they usually do, the prosecutors in this case are providing jurors with definitions of possible crimes so they can decide what charges, if any, are warranted.

"The grand jury will be given a range of potential charges, from murder first to involuntary manslaughter, just as they would in a jury trial," said Edward Magee, the prosecutor’s spokesman. The panel will also be instructed in the statutes governing self-defense and the use of deadly force by law enforcement agents.

The most likely crimes to receive consideration, legal experts said, were:

» Second-degree murder, defined as "knowingly causing the death of another person" and punishable by prison terms of 10 to 30 years;

» Voluntary manslaughter, which is causing a death "under the influence of sudden passion arising from adequate cause," with a penalty of five to 15 years;

» Involuntary manslaughter in the first degree, which can mean "recklessly" causing a death, with a penalty not to exceed seven years;

» Involuntary manslaughter in the second degree, which is acting "with criminal negligence" to cause a death, with a penalty not to exceed four years.

The grand jurors will also have to consider the grounds for official use of deadly force, which is legal when an officer "reasonably believes" that a person "may otherwise endanger life or inflict serious physical injury unless arrested without delay," as well as a broader self-defense clause, which allows anyone to use deadly force when he or she "reasonably believes" it is necessary to prevent death or serious injury.

Jurors will have to assess the varied eyewitness accounts, the forensic evidence and the law and make a decision.

"At bottom would be their view of the reasonableness of a belief that his own or someone else’s life was in jeopardy," Goldwasser said. "If you think that it was reasonable, then you don’t charge him. If you think it was unreasonable, you charge."

The grand jury had already been meeting weekly since May, voting on indictments in more routine cases that prosecutors wanted to bring, when they were assigned to the Wilson case in August and the jurors had their terms extended.

What message might have been sent, Goldwasser wondered, when prosecutors shifted tactics so radically, offering evidence from all sides in a case?

Another factor with unknown consequences: The jurors have not been sequestered, making it virtually certain that they would have heard a great deal about the case even if they tried to avoid it.

This is not usually a major concern at the grand jury stage, which determines only whether there is probable cause to indict a person before a full-fledged criminal trial with more limits on permissible testimony.

On Thursday, Gray, the Brown family lawyer, reiterated his concern about the grand jury proceedings, saying he worried about possible bias in the way information was presented. "What emphasis was placed on what piece of evidence?" he asked.

The prosecutor, seeking to allay such fears, has arranged for the proceedings to be recorded, "just to be open," said Magee, the spokesman. If the grand jury does not vote for an indictment, the prosecutor will ask the court to authorize the public release of transcripts and recordings, without witness names, Magee said.

Erik Eckholm and Julie Bosman, New York Times

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