Abu Dawud Book 24, Hadith Number 3938.

Chapter : Possession of a slave who is a relative to the master and is within the prohibited degrees.

Narated By Samurah : The Prophet (PBUH) said: (The narrator Musa said in another place: From Samurah ibn Jundub as presumed by Hammad): If anyone gets possession of a relative who is within the prohibited degrees, that person becomes free. AbuDawud said: A similar tradition has also been transmitted by Samurah from the Prophet (PBUH) through a different chain.