The Pozner family had the noahpozner.com website transferred to its ownership. Victoria Haller, Noah's aunt, emailed the person who had originally registered the name. The person, who went by the name Jason Martin, wrote back that he'd meant "to somehow honor Noah and help promote a safer gun culture. I had no ill intentions I assure you."

Alexis Haller said the experience "should serve as a warning signal to other victims' families. We urge people to watch out for these frauds on social media sites."

Consumer groups, state attorneys general and law enforcement authorities call for caution about unsolicited requests for donations, by phone or email. They tell people to be wary of callers who don't want to answer questions about their organization, who won't take "no" for an answer, or who convey what seems to be an unreasonable sense of urgency.

"This is a time of mourning for the people of Newtown and for our entire state," Connecticut Attorney General George Jepsen said in a statement this week. "Unfortunately, it's also a time when bad actors may seek to exploit those coping with this tragedy."

But scam artists know that calamity is fertile ground for profit, watered by the goodwill of strangers who want to help and may not be familiar with the cause or the people they're sending money to.

After the shootings at Columbine High School in Littleton, Colo., scammers asked for credit card donations for victims' families. After the 9/11 attacks, the North American Securities Administrators Association warned investors to be wary of Internet postings encouraging them to invest in supposed anti-terrorist technologies.

In 2006, the FBI warned about an email widely circulated after the Sago, W.Va., mine explosion, which claimed to be from a doctor treating one of the survivors and asking for donations to cover medical bills.

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