Well, it is not legal to shoot someone for stealing in Minnesota so I'm not sure how this would be lawful violence. He would need to have said something like "when the looting starts, we will attempt to arrest anyone that we see, if they then threaten the officers' lives instead of stopping or running away, then the shooting starts".
It is NOT legal for the Minnesota police to shoot a citizen that they believe is committing a crime unless their life or another person's life is under direct threat.