That is not mentioned in the source I had nor the source OP posted. Your source also doesn't say she said it though. Just that someone in the group said it.

I still don't think someone saying the N-word is a reason to shoot at a whole group of people and possibly hit someone standing next to them, but at this point I would be making assumptions too. We need more info.

But is it really right to shoot someone for calling you a name? Let's talk about that now... I have no idea what to say there. Like I would get it if a black person shot someone back then for saying it, because that person could be a threat to their life, but I honestly just see it as name calling at this point 150+ years later and since slavery was abolished... Non of these black people had anything to do with that and I don't see the emotional charge carried with that kind of reaction as entirely justified.