If, as the article stated, Mr. Singletary asked them to leave his property and they refused, then it is most definitely a wrongful death. Just because the cops are impersonating thugs doesn't mean they can ignore this man's property rights. So what if real thugs would not have left. They're cops, they should have left immediately.
After the situation calmed down, they could revisit Mr. Singletary and suggest in the strongest possible terms that he leave drug fighting to them.
However, from the info in the article, they are culpable and should be held accountable.
There is not enough information. We don't know who fired first. We don't know what the resident said to the cops. I do not have specific knowledge of Florida laws but would you think the cops culpable if the resident fired first? Does a Florida homeowner have a legal right to shoot anyone in his yard who fails to leave when ordered to?