Hadith.3519 - Hisham ibn Salim narrated from Abu Basir, from Abu Ja'far Imam Muhammad ibn Ali Al-Baqir (as):
"Commander of the Faithful, peace be upon him, ruled regarding a person who mistreated his slave that the
slave becomes free. There is no authority over him, and he is considered a 'sa'ibah' (free without obligation). He may choose to align himself with whomever he wishes, and if that person guarantees his liability, then he inherits from him."