If was either a hoax, or a demon manifestation, if they actually saw something.
There are many eyewitness accounts in the archives at Fatima Shrine. They saw ‘something’ and it made physical effects upon the wet clothes and the ‘burned skin’ of some witnesses. It also cause gasoline to spontaneously combust and a real photo was made showing a disc in the sky over the apparition site. The local priest who took the eyewitness accounts was convinced the whole thing was demonic, but the Org moved him away from the region. The apparitions began showing up in May and the big event took place in October, IMS.