This state observes a "stand your ground" rule that permits anyone to kill when accosted by an armed aggressor, Summer said.

That means Oakley could be legally justified in killing if Baker came at him with a broken bottle -- a deadly weapon -- and was not running away. Georgia law also permits a third party, such as Lewis, to use deadly force in defense of someone whose life is being threatened, Summer said.

Complicating the job for the jurors is the fact that the brawl raged up and down a sidewalk crowded with people pouring out of bars that had just closed. The limousine was parked mid-block, near a stubby tree. The victims were found 52 feet away, on the pavement in an intersection.

Witnesses have been identified who were in an apartment building overlooking the sidewalk or who were driving by and stopped to intervene. But few of them had an unobstructed view of the entire fight, except members of the victims' and Lewis' parties, whose testimony is contradictory and bound to be viewed skeptically by the jury.

The physical evidence is also confusing. Blood from one of the victims has been found in the limousine, including in an area where Lewis was sitting. But no blood was found on the football player's clothing, a source said. And police have been unable to conclusively link a mink fiber found gripped by one of the dead men to fur coats worn by Lewis or others that morning.

No murder weapon has been recovered. A knife found at the scene had no trace of blood, and, because of the texture of its handle, produced no usable fingerprints.

Investigators have found witnesses and receipts indicating that Sweeting bought three knives -- including one matching the make and model of the weapon found at the crime scene -- while he was with Lewis and Oakley at a sporting goods store two days before the killings.

Still missing is the gun that someone used to fire five shots at the limousine A friend of the victims has come forward to say that he got the gun from a car and shot at the limousine as it pulled away, then later disposed of the weapon.

But Sweeting's attorney has suggested in court filings that the gun was taken from Lollar's body after he was killed. Shell casing found atop the bodies appear to support that theory.

Jurors are bound to wonder, too, why everyone fled the scene. Lewis' group took off in the limousine; police caught up to it when they got a tip that the vehicle was a few miles away with a flat tire. But its passengers had all left in cabs by then. The limousine driver, who remained behind, told police that he overheard someone in the back say, "I stabbed mine." He told prosecutors that he was warned by Lewis not to reveal who was in the vehicle. "It's going to be difficult for the state to present one picture, a still picture," Froelich said.

Sun staff writer Marego Athans contributed to this article.