My farther bought a property with his haraam earnings .Is it halaal if i sell the property and start a new business?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

If your father had earned the money with which he bought this property from Riba (interest and/or usury), cheating and the like, then it is permissible for you to benefit from this property if it was transferred to you by being gifted to you or by you inheriting it, but if he had bought it with money earned through theft, or money taken unjustly and so forth, then it is not permissible for you to benefit from this property.

Shykh Ibn ‘Uthaymeen said: “What is forbidden due to the way it is earned is forbidden only for its earner, like Riba, if the person who deals with Riba dies, his money becomes lawful for his heirs, but if something is forbidden in itself, like intoxicants [alcohol] then the money (earned from that) is forbidden for the one who leaves it and the one to whom it is left. Similarly, what is forbidden and remains forbidden like the money [or something] that was stolen or taken unjustly, like if someone steals for example and then dies, what is stolen is not permissible for the heirs. Rather, if its owner is known, it should be given back to him; otherwise, it should be given in charity while indenting the reward for its owner."

Allaah Knows best.