´It was narrated that Ibn 'Abbas said:` "The Messenger of Allah ruled that the Diyah for a Mukatab who is killed should be (equivalent) to the Diyah for a free mand, proportionate to the amount be had paid off (toward buying his freedom)."
Hadith ReferenceSunan an-Nasa'i / The Book of Oaths (qasamah), Retaliation and Blood Money / Hadith: 4812
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:ضعيف، إسناده ضعيف، ابو داود (4581) انوار الصحيفه، صفحه نمبر 357