A. I assume your question refers to funds left by deceased relatives. If that is the case, and provided there is no will, you would have to file an intestacy procedure in order to obtain a sentence giving the right of ownership of those funds.
However, in order to commence any proceedings, you would need to know whether the existing assets object of the claim are of a value enough to make the legal expense worth the while.
If you know there are assets but you have no other details, the a search is necessary. For example, you could do a search for funds in the bank(s) where presumably an account is opened in the name of the relative. Once those funds have been identified, the intestacy procedure can be filed.