In the world as far as we know, if we cannot see it, that does not mean it does not exist, hardly are we concerned with what our eyes can not see, except a majority of it, are feelings being reciprocated.
Whether it may be a dog barking at something or a cat snaring, could it be that it is something they can witness?
Believing in a life after death is a consequence of being living, perhaps there is so much to explain that there is no reason to speculate anything.
It would be just a guess or myself assuming of the unnatural occurrences.
If something unnatural happens, know that the jinns are amongst us in this world.
Indeed, shaitan and his comrades are dwelling in the unseen, they are also close to a human, so there is without a doubt, things can appear but does not mean they have much power to do with it.
The angels are close to us as though they are our jugular vein.
The most important part is, He knows the unseen aspect of the heavens, the earth and all that is between.
The soul of the human is somewhere indeed.