Edna Bette-Jean Masters disappeared on July 3, 1960, as she was playing at a friend's house in the Red Lake area, west of Kamloops in B.C.'s Interior.
Her disappearance prompted a massive search, but police and search-and-rescue personnel were unable to turn up any sign of her.
Now, investigators plan to use new technology, such as DNA examination and software that digitally ages photographs, in an effort to generate new leads in the case.
Cpl. Cheryl Bush points out there has never been any evidence to suggest the girl is dead, raising the possibility Masters, who today would be 55 years old, is out there somewhere.
"There is a possibility that this person is still alive. There was never any evidence found to the contrary," Bush said Monday.
"If that's the case, then maybe this will spark somebody to ask some questions that they always wondered about their past."
Masters, who was referred to by her middle name, Bette-Jean, was last seen playing with family and friends at a friend's residence.
The young girl, who had curly blonde hair, blue eyes and a fair complexion, was wearing a green bonnet, a pink T-shirt and faded overalls at the time. She had an oval-shaped burn scar on her left arm, which investigators believe would still be there today.
When Masters was reported missing, the surrounding area was searched extensively. RCMP officers used an airplane and a police dog and enlisted the help of volunteers, but they were unable to turn up any trace of Masters.
One of the only leads was a sighting of an unfamiliar 1959 Chevrolet car with Alberta plates that was seen nearby with a man and woman in their late 20s. The car had either "cat eye" or "bat wing" tail lights, the RCMP said.
Investigators have never been able to determine the identities of the couple or whether they were connected to Masters' disappearance.
Masters' mother and two siblings are still alive and still wondering what happened to the young girl, said Bush.
Bush said police hope the attention to the case might prompt someone to remember a detail that could be related, no matter how seemingly insignificant, and contact police.
She said such reviews are routine in historic missing-person cases.
"It's part of our standard practice to review these files, just like any other RCMP detachment in the province, particularly for historical cases that were investigated prior to new technology or investigative techniques," she said.
Bush did not have any details about what specifically the review will involve or how long it might take.
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