The family of Noah Pozner was mourning the 6-year-old, killed in the Newtown school massacre, when outrage compounded their sorrow.

Someone they didn't know was soliciting donations in Noah's memory, claiming that they'd send any cards, packages and money collected to his parents and siblings. An official-looking website had been set up, with Noah's name as the address, even including petitions on gun control.

Noah's uncle, Alexis Haller, called on law enforcement authorities to seek out "these despicable people."

"These scammers," he said, "are taking away from families and the spirits of dead kids."

It's a problem as familiar as it is disturbing. Tragedy strikes -- be it a natural disaster, a gunman's rampage or a terrorist attack -- and scam artists move in.

It happened after 9/11. It happened after Columbine. It happened after Hurricane Katrina. And after this summer's movie theater shooting in Aurora, Colo.