RCMP say the child was injured in an accident Sept. 18 while playing outside with other children in Maskwacis, formerly known as Hobbema, about 85 kilometres south of Edmonton.
She died nine days later in hospital.
RCMP spokeswoman Sgt. Josee Valiquette said Thursday that police became involved the day after the accident because of the severity of the girl's injuries. She wouldn't say how the girl was hurt.
"There was an accident but, until we can be sure this is the cause of her death, we're involved in this matter," said Valiquette.
"We want to make sure there is no criminal element to this."
She said an autopsy has been completed but results likely won't be available for a few weeks.
Also on HuffPost