Public safety announcements and police departments have advised parents to inspect their children's candy before letting them eat it.
But a University of Delaware professor says this is not a real problem. He considers it an urban legend, and a stubborn one.
Joel Best is a professor of sociology and criminal justice at the University of Delaware. He has studied concerns about contaminated candy since the 1980s. Best has collected data going back to 1958.
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"I cannot find any evidence that any child has ever been killed or seriously hurt by a contaminated treat picked up in the course of trick or treating," Best told Action News.
He says he found one case of a man in Texas murdering his own son with poisoned candy because he thought it would be the perfect crime assuming other children died that way.
There was another case in California where a girl's death was first attributed to candy contamination. The autopsy later confirmed she died of natural causes.
As for reports of needles or razor blades being found in Halloween candy?
"Halloween is a holiday for pranking," Best said. "We've run out of outhouses to tip over, and so we do other things. You take a pin. You stick it in a candy bar. You run into your mom and say, 'Look, Mom, look what I've got.' You're rewarded with the concerned attention of adults."
When people try and follow these things up, they've discovered all of them are hoaxes.
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So does he think parents should check their kids' candy?
"I didn't check my kids," he said. "You know, if it makes people feel good to do it, it's fine with me. I don't think it's necessary."