In the chaotic days after Hurricane Katrina, an order circulated among New Orleans police authorizing officers to shoot looters, according to present and former members of the department.

It's not clear how broadly the order was communicated. Some officers who heard it say they refused to carry it out. Others say they understood it as a fundamental change in the standards on deadly force, which allow police to fire only to protect themselves or others from what appears to be an imminent physical threat.