Question about inheritance

My parents was killed in a caraccident late last year. My father (turk) died instantly while my mother (finnish) died a month later.
I have discovered that my father have a lot of other children in earlier marriages besides me and my brother.
What are these half-siblings allowed to inherit? I understand that my mother inherit from my father since she passed away a month later.
Can these half-siblings, some who i have never met before, have any right whatsoever to funds or properties that lies solemnly under my late mothers name?
Does it complicate the case if my father and mother where of dual citizenship? Me and my brother are dual.

According to the Turkish civil code which have to be applied to your father due to his citizenship, 1/4 of his belongings go to his wife and the rest should be shared equally between his children.

Cumulus: i'm not a lawyer, but just wanted to say that I'm very sorry for you on 2 counts, about the loss of your parents & about you discovering that your father kept his other children secret from you. I can only imagine the shock to you, but believe me it is not uncommon, I have heard many such stories & have one of my own.

Please don't blame your half-siblings for anything, they are also victims of lies in this. I was a wife of a Turk too and not only did he walk out on me & our kids, but he never told his new wife about our children, he disowned his children for pure selfish & cowardly reasons. I don't know the reasons for your father's lies & secrets, but they were his lies, not that of your 1/2 siblings. Consider that you have gained & dicovered new family members, perhaps a small consolation for the incredible loss of your parents.

Best of luck.