Ambush \Am"bush\, v. i. To lie in wait, for the purpose of attacking by surprise; to lurk.
But if the reporting on what happened is accurate, it was exactly the opposite of an "ambush." Let's look at the timeline according to the New York Times:
8:40am -- 911/Baton Rouge police dispatch receives "a report of a man walking on Airline Highway carrying a rifle." Now, I suppose that if Gavin Long was looking for a fight he was going to find one, but this is a little bit puzzling. "Open carry" is perfectly legal in Louisiana, so the appropriate response from 911 would have been "ummm ... so? Get the hell off this line -- it's for emergencies and crimes."
Instead, officers respond to the scene where "the man, dressed in black, was seen standing behind a beauty supply store."
They knew where he was. They knew he was armed. They had been told those things, then they went there in force and saw him. That's not an "ambush," unless it's the police doing a "hasty ambush" operation in which they were the ones hiding or disguising themselves in order to surprise Long.
8:42am thru 8:45am -- Shots are reported, officers are reported down behind the beauty supply store, and shots are reported again.
8:46 -- Long is reported to be near a car wash next to the beauty supply store, and eyewitness video shows police firing in that direction from behind a squad car. Long is killed.
Again, hardly an "ambush" if they knew where he was and now knew that he was not just armed but shooting.
Right now, the big project -- with which both law enforcement and media are preoccupied -- seems to be tearing into Gavin Long's life to figure out why he went looking for a fight with the cops.
But what if he didn't go looking for a fight with the cops?
Historically, it is not especially unusual for black men to go armed by way of protecting themselves or their communities during times of racial tension. The Black Panthers conducted armed counter-police patrols in Oakland in the '60s (and possibly elsewhere and elsewhen). During the earlier civil rights movement, people and organizations who weren't nearly as radical did so as well, especially in the south.
What if Long was doing precisely that -- going armed as a measure of self-defense and/or protest -- when the cops attacked him? Is it possible that he acted entirely in self-defense? As mentioned above, there was no particular reason for Baton Rouge police to respond to a report of a man engaging in completely legal conduct, yet they apparently sent a sizable force to the scene.