What is the ruling regarding my acceptance of a gift or inheritance from a property that my father purchased with money usurped from the state, given that I do not know whether all of this money is unlawful or mixed with lawful money?

The money of an employed father is mixed, and it is permissible to deal with it in matters of gifts, inheritance, and the like, due to the lack of certain knowledge that he purchased with the stolen money itself, or that he purchased on credit and then paid from lawful or other sources, or from both combined.