My great grand parents from my mother's side (born circa 1900) left Spain in the first quarter of the 20th century to move to France where my grand father was born in 1925. They left Spain because they were looking for better living conditions and started working as daily workers in the south east of France. My great grand father built my village's wine cellar among other things that are still standing today and became a great figure in my village.
I was very interested in trying to find out if they had relatives who stayed in Spain, but when I asked my mom she couldn't answer because her own father who passed away pretty young never told her. He did also not tell her where they used to live in Spain. Besides, when they moved to France they shortened their last name to only 3 letters so it is very difficult for me to find a trace of that.
Do you have any idea on how I could investigate on that without having to go to Spain to check that out?