When other cops arrived, they saw-- not a cop with his badge visible chasing a suspect -- but a man with a gun drawn, chasing someone.
What happened after that isn't completely clear, although the fog is beginning to lift.
Did the off duty cop identify himself? Did he turn to face his comrades? Did anyone say anything before the first shot was fired? Or the sixth? Did the off-duty cop even know the other guys were police officers, because they too were in civilian clothes?
Late this afternoon, police officials said that, yes, the officer who fired six shots at Edwards -- three of them hit - identified himself and ordered him to put down the gun.
Police officials also say the suspect who was being chased - Miguel Santiago - also heard the cop identify himself, and saw three cops with badges around their necks.
And one of the officers on the scene said that that the off-duty officer, Omar Edwards, turned towards the cop who fired the shots, with his gun in his hand. The two officers were just 15 feet apart.
The tragedy is that Edwards, 25, two years on the job, with two young kids, a new wife, is dead.
And the officer who shot him -- well, his life is changed forever. Can you imagine their reaction when they ripped open Edwards shirt and found him wearing a police academy t-shirt, and then found an NYPD badge in his pocket?
The NYPD procedure seems clear: When an off-duty cop has his gun drawn on a suspect, and on-duty cops arrive, the off-duty officer yields the situation. Period. The onus is on the off-duty officer.
What makes the case politically charged is race. Omar Edwards was black. The officer who shot him three times is white. The suspect Edwards was chasing is Hispanic.
Did officers arrive on the scene and see a fellow cop chasing a suspect, with his gun drawn. Or did they see a black man, gun out, chasing a Hispanic man down the streets of East Harlem late at night?
Is race a factor? There are those tonight who say it is. The Rev. Al Sharpton says black off-duty cops getting shot is happening too often, and he wants a federal investigation.
The officers who confronted Edwards were members of the NYPD's anti-crime unit - once the street crimes unit. They are plainclothes officers, patrolling the streets, and they're typically selected for their "observational skills."
There are so many components to this story -- all of them complicated, all of them tragic.
And I can't help but think of Officer Edwards - all the choices he made last night. Why did he pull his gun to confront a car burglar? Why did he chase him? Did he let the guy know he was a cop?
And what of the officer who fatally shot Edwards? How many times is he replaying the scene, wondering if he could have, should have, done all this differently.
We will likely not find out tonight everything that happened - but the answers are there, because at the intersection E. 125th St. and Second Ave. in East Harlem, there are several NYPD surveillance cameras.
We're following the developments, tonight at 11.
We'll also have any breaking news of the night, plus Lee Goldberg's weekend AccuWeather forecast (and you can read Lee's Blog or Bust by CLICKING HERE), and Scott Clark with the night's sports. I hope you can join Liz Cho and me, tonight at 11, right after 20/20.