Sahih Muslim Book 9, Hadith Number 3595.

Chapter: The right of inheritance of property vests with one who emancipates the slave.

Abu Huraira (Allah be pleased with him) reported: ‘Aisha (Allah be pleated with her) thought of buying a slave-girl and emancipating her, but her owners refused to (sell her but on the condition) that the right of inheritance would vest in them. She made a mention of that to Allah’s Messenger (may peace be upon him) whereupon he said: Let this (condition) not stand in your way for the right of inheritance vests with one who emancipates.