How to find the owner of a property?

Hi there
I'm trying to find the owner of a property with an old ruin in the Monchique area in the Algarve.
I already tried to ask the neighbours but nobody seems to know whom it belongs to.
Do you have any ideas or experience how to find the owner?
Thanks for any answers.

Try the town hall/council?

hello
you can try to see the coordinates on google maps, take them to camara municipal and they may have that info for you.  sometimes is hard to find when the person passed away and their children did not update the records in camara, finanças and conservatoria.
good luck