Ibn ’Abbas (RAA) narrated that The Messenger of Allah (ﷺ) said:
“The Diyah (Blood money) of a slave who had made an agreement to buy his freedom (Mukatib) and had been killed, is paid at the rate paid for a free man (as a Diyah) as much as he has paid of the amount agreed upon, and at the rate paid for a slave as the remainder is concerned.” Related by Ahmad, Abu Dawud and Au-Nasa’i.