Hecksher State Park Beach on New York's Long Island. Image: Wikipedia.

Police and parents are trying to figure out why staff of a New York-area day care facility left a 2-year-old girl at the beach after a trip there, then waited three hours to alert authorities the child was missing, Long Island State Park Police said.

"In between that three hours, we were calling the local precinct, all over the place," said Capt. Bruce Marx of the Long Island State Park Police.

Police say they believe Our Little Darlings Day Care, of Bay Shore, N.Y., left the Hecksher State Park beach at around 3:10 p.m. on Tuesday with a group of children, but without the 2-year-old girl.

A mother, who watched the toddler play with her kids, realized something was awry when she got ready to leave at around 3:30 p.m. and could not find anyone to claim the child.

"She apparently wants to leave and realizes there's no parent around, so she walks the baby over to a lifeguard and she says, 'Hey, I don't know what's going on here,' and the police were notified," Marx said.

Our Little Darlings Day Care called the station at 6:21 p.m. to ask if a child had been found.

Police notified the child's mother, who was "extremely distraught" when she got word of what happened, Marx said.

The child, who was unharmed, was returned safely to her mother.

Police said no charges have been filed and the investigation will continue.

The day care center could not be reached for comment.