(CNN) Three children who were playing outside climbed into an unplugged chest freezer and died after the lid closed and they were unable to get out, a sheriff in northern Florida said.

A woman who was with the children on Sunday had gone inside to use the restroom when the children disappeared at a home in Live Oak, Suwannee County sheriff's officials said.

Two girls, age 1 and 4, and a 6-year-old boy got into the freezer.

The woman returned to the yard, could not locate the children, woke up another woman and they began to search the property and area, authorities said. They opened the freezer and began resuscitative efforts before calling 911. First responders were unable to resuscitate the children, either.

"Upon further inspection of the freezer, an after-market hasp had been installed on the lid in order to secure a padlock on it," the sheriff's office said in a Facebook post. "It is believed at this time, that when the children entered the freezer, and the lid closed, the hasp fell shut, trapping the children inside. There was no padlock on the freezer."

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