Please set me straight if I am misreading your statement, but it sounds like you are not aware that Blackwater and AmourGroup were in NOLA right after Katrina. For example, this article.

I found it a bit disturbing in Katrina. Although the particular Washington Post article I referenced only mentioned that the contractors carried sidearms, other news articles from that time mentioned that they were heavily armed (well, like with M4's and body armor, not heavy machine guns). Some had even recently returned from tours in Iraq, and heaven only knows what kind of reflexes and responses you developed from being over there. In one article, one Blackwater contractor flashed a badge at the reporter and said that they'd all just been federally "deputized"--whatever that meant in this case and no one would say what agency deputized them. Could they arrest people? No one said. Anyway, it sounded like a recipe for disaster to me at the time.