IT HAS BEEN nearly two weeks since 22-year-old Oscar Grant III of Hayward was shot in the back by a BART police officer while Grant was lying facedown on a platform at the Fruitvale station — an event captured in cell phone videos by train passengers and beamed around the world via the Web.

That's long enough to start getting some answers about what happened. Yet still, we know nothing.

The officer accused of firing the fatal shot, 27-year-old Johannes Mehserle, has refused to talk to either BART investigators or Alameda County District Attorney Tom Orloff — and has since resigned from the BART force. Yet Mehserle has not been detained and no charges have been filed against him.

Mehserle is well within his constitutional rights not to give information that could incriminate him.

But his failure to cooperate with investigators feeds into public perceptions that he is guilty of a criminal act rather than someone who made a tragic mistake. Given the heated emotions in this case, why didn't Mehserle's attorney issue a statement of regret for the "tragic accident" — or whatever other words he might have chosen — to at least have his client express remorse over the loss of this young man's life?

Even the BART board understood the importance of saying it was sorry.

In the vacuum that has been created by the absence of facts, the grainy video tapes have become the truth in many people's minds.

As we wait for the district attorney to announce the findings of his investigation, I wonder what possible conclusion would satisfy an understandably outraged community.

As I wrote last week, we must not rush to judgment based on snippets of cell phone videos alone. We must refrain from trying this case in the media and on the Internet.

But by the same token, BART and our elected officials have to do their part to cool down the climate. They have to be respectful of the community. Understand the anger and frustration when a young, unarmed African-American man lying on his stomach is shot dead by a police officer — and that this is not going to be viewed, and must not be treated like, just another Oakland homicide.

That's because there is a history in this country of police shootings of young African-American men. So when one occurs, however infrequently, it touches a raw nerve.

That is why BART and the district attorney investigating the case must be extra careful to give the right signals so that the public perceives that justice is going to be served.

Yet there appears to be an almost blase response on the part of BART and the district attorney — as though they don't realize that they're sitting on a powder keg, though the near-riots last week should have given them some indication.

I lived in Los Angeles when that city erupted in 1992 after the verdicts in the Rodney King beating case. I can tell you, it doesn't take much to set a city burning.

I can understand that Orloff's office doesn't want to rush to judgment. It shouldn't.

What I don't understand is why it would take another week and a half for Orloff to complete its investigation when BART investigators have presumably already done the legwork.

With Grant lying facedown, there is next to no possibility that the officer felt his life was in danger, that someone else's life was in danger, or that Grant was going to escape. Those are the only justifiable grounds for use of lethal force.

So, either the officer fired the weapon by accident, or he deliberately used unjustifiable lethal force.

What does the district attorney do with the evidence — the information on the videos, the statements from the witnesses, and nothing from the officer?

"You charge for the top crime it could be," says Franklin Zimring, a professor at UC Berkeley's Boalt Law School. who specializes in criminal law.

That top crime, he says, would be second-degree murder — which automatically includes the lesser possibilities of voluntary or involuntary manslaughter.

There is, of course, the possibility Orloff will decide there isn't enough evidence to file criminal charges.

But if that were to be the case, says Charles Weisselberg, a criminal procedure expert at Boalt Law, "he will want to think carefully about how to state that to members of the public."

Tammerlin Drummond is a columnist for the Bay Area News Group-East Bay. Her column runs Wednesday in metro and Sunday in opinion. Contact her at tdrummond@bayareanewsgroup.com.