From your link...interesting
"Michael Arntfield, a criminologist at Western University in London, Ont., called the case "unprecedented," saying it's highly unlikely for two siblings who live together to vanish when a parent is not involved.
"And there's no evidence of that. If that had been the case, I think we would have heard about that very quickly," he said."
"This case, when you overlay it on a hundred other missing children cases, it just doesn't add up at many levels."
(...)
"I'm giving them [LE] the benefit of the doubt that there is some active lead being worked and they don't want to upset the equilibrium that they're in," said Arntfield.
"But based on appearances, this went in the wrong direction early on and key momentum and leads were lost when they were out in the fields looking for kids that maybe were never there."