According to several sources, walker did start shooting before he identified his target, just as the door was being smashed in. Here's one.
We gathered the facts based on public records, official statements and interviews with witnesses and people close to the case to knock down myths.
www.courier-journal.com
It is unknown if he was involved in dealing narcotics, I'm wrong on that count.
The police did announce their presence according to the above NY times article, despite it being a no-knock warrant.
Overall to me, this looks like a really unfortunate circumstance that just went south and I'm not sure that this had obvious racial motivation. Is their evidence to the contrary? Would genuinely like to know because if so I'm scared of no-knock warrants.