Maybe if the people had been told that LE had jurisdiction over all goods and that no one was going to go hungry and a show of force had been done up front, a lot of this could have been avoided and supplies could have been handed out accordingly.
The looters know they can steal without being arrested. Obviously they are stealing much more than food, so I doubt that informing them that they weren't going to go hungry would have altered their behavior a whit.
What sort of "show of force" did you have in mind? The looters are armed and are willing to shoot at the cops. Did you want the cops to return fire?