The family of 7-year-old Sloan Mattingly, an Indiana girl who died on a South Florida beach last week when a deep sand hole collapsed on her and her brother, has revealed new details about the tragic accident.

Sloan was digging a 5- to 6-feet deep hole with her 9-year-old brother Maddox in Lauderdale-by-the-Sea while on vacation with their family, when the sand hole suddenly caved in. Sloan was buried alive in the sand while Maddox was covered nearly up to his neck.

Sloan’s uncle, Chris Sloan, detailed to KFOR-TV how the first-grader tried to grab up at her brother’s leg during her final frantic moments after the collapse.

"Later we found out that after the sand had caved, she kept trying to grab up Maddox’s leg to get up out of the sand, and eventually he couldn’t feel her moving anymore," he said. "The sand had been up to his chest, and he was screaming for help, and a lot of people did come and help."

TRAGIC FLORIDA SAND HOLE DEATH COULD HAVE BEEN PREVENTED: EXPERT

Dramatic video posted online showed several beachgoers frantically trying to dig through the sand and reach Sloan. They were trying to hold on to the walls of the hole, so it would not collapse further. The fire department said it used support boards to keep more sand from collapsing in as they used shovels to dig the children out.

Chris Sloan said that as far as the family knows, Sloan was found unresponsive at the scene.

Sloan was pronounced dead on arrival at a nearby hospital, while Maddox was in stable condition. 

GIRL BURIED ALIVE WHILE DIGGING SAND HOLE IN FLORIDA, BROTHER INJURED

The children’s mother, Therese, addressed what she called a "freak accident" in a statement on a GoFundMe campaign set up for the family.

"We experienced the purest human being and we are forever changed by her," the mother’s statement said. "We love you beyond any stretch of the imagination. Our sweet Sloan. What we would give."

Chris Sloan told the news outlet that the family hopes that sharing Sloan’s story will prevent other families from experiencing this type of tragedy.

"This is real. It’s tragic. It’s happened," he said. "We’re working through it, and hopefully nothing like this ever happens to anyone else ever again."

Fox News’ Michael Dorgan contributed to this report.