This case reminds me of little Emile S. in the French Alps.
Nobody really knows what happened.
He allegedly wandered off from grandparents' house.
Searches were not successful.
Then,
one day,
a hiker found a little skull on the track.
His clothes were discovered later in the area previously searched.
Such a heartbreaking case

He was only 2 and a half years old.
He looked like a little Angel, just like Gus
The case remains under investigation,
and the cause of Emile's death has not been formally established.
There is a thread on WS about this tragedy.
J