When citizens of entire cities were evacuated in the aftermath of Hurricane Katrina that meant everyone, including prisoners and registered sex offenders.
Approximately 25 percent of sex offenders on the Gulf Coast are currently out of compliance with their parole, probation or registry requirements.
"Obviously, Katrina changed a lot of the rules here in Louisiana," said Lt. Lawrence McLeary of the Louisiana State Police. "And it exposed a lot of the vulnerabilities in the sex offender registry that we didn't even know existed."
In Texas, Andy Kahan of the Houston Crime Victim Assistance Program noted that the whereabouts of the approximately 15,000 sex offenders forced to relocate is "the million dollar question."
Until they solve that question, they're counting on help from the public.
"I'm sure that the citizens there are notifying the authorities that this person is a sex offender," Kahan said. "They know that for a fact. And the citizens' eyes and ears are going to be invaluable help to us."
According to Louisiana state law, sex offenders have 10 days after a relocation to register their new address. And officials in states like Texas, where thousands of evacuees now reside, say time is up.
"If you don't let us know, I guarantee you, you're going to end up with a one-way ticket back to jail," Kahan said.
At Camp Edwards, a shelter in Massachusetts that is home to more than 200 evacuees, officials found seven sex offenders. Some now live in separate housing, one sent to a local jail. In Philadelphia, background checks are under way. And now Louisiana officials are making records available to help police in other states.
"Our database, it not only has those physical characteristics of that individual and all those identifiers, Social Security, previous address, but it has pictures in there, too," said McLeary.
The government has also stepped in to help. Last week in Washington, the House approved the Children's Safety Act, which would create a national Web site for child sex offenders and stipulates the sex felons face up to 20 years in prison for failing to comply with registration requirements.
Still, officials say caution is paramount when dealing with anyone you don't know, under any circumstance.
"Be very careful of who you take on your home," McLeary said. "Keep close eye on your kids and know where they are at all times."