SELBYVILLE, Del. -- A 4-year-old girl mistakenly took hundreds of packets of heroin to her day care centre and began passing them out to classmates, thinking the drug was candy, Delaware State Police said Tuesday.

Several children who received the packets Monday morning went to the hospital as a precaution, police said. But no packets were opened, and all of the kids were released after being examined.

Police say the child unknowingly brought the heroin to the centre when her mother gave her a different backpack because the girl's regular backpack had been ruined by the family pet. Police say the backpack contained nearly 250 packets of heroin, totalling nearly 4 grams (0.14 ounces), all labeled "Slam."

The girl's mother, Ashley Tull, 30, of Selbyville, was charged with three counts of child endangerment and maintaining a drug property. She was arraigned Monday in Justice of the Peace Court and released on $6,000 bond.

In a phone interview Tuesday, a woman who identified herself as Tull's sister, Alicia Tull, said Ashley Tull would not comment. But Alicia Tull said the charges and the subsequent media attention are unfair.

Alicia Tull said her sister had no idea that heroin was in the backpack and would not have sent her daughter to school with the backpack if she had known. She said that Ashley Tull does not use or deal drugs and that she was taken advantage of by an individual who stored the drugs in Tull's home without her knowledge.

The child endangerment counts relate to Tull's three children, who range in age from 11 to 4. As part of her release, Tull was ordered not to have any contact with her children, who are in the custody of a relative, according to police.

The charge of maintaining a drug property means that a person knowingly allows drugs in the home, said Delaware State Police spokesman Master Cpl. Gary Fournier. It is a distinct crime from drug possession.

Fournier declined to comment Tuesday on details of the investigation. Police have said their investigation continues and more charges could be forthcoming.

Fournier said he believes the day care centre, the Hickory Tree Child Care Center in Selbyville, handled the situation properly, and notified police immediately when it occurred.

A call to the centre was not returned Tuesday.