When you think of crimes related to Hurricane Katrina, looters come to mind.
But the federal government is focusing on sex offenders. Officials estimate some 2,000 registered sex offenders fled the storm and re-settled in other states.
And many of those have failed to re-register.
The administration for children and families in Washington sent a letter to state governors warning them of displaced sex offenders.
Mississippi estimates it has accounted for all but a fraction of offenders missing since Katrina.
However, New Orleans, with a much larger sex offender population, still has hundreds unaccounted for.