(45) The Book of Oaths (qasamah), Retaliation and Blood Money
كتاب القسامة
(38, 39) Chapter: The Diyah for a Mukatab
(38, 39) باب دِيَةِ الْمُكَاتَبِ ‏‏
Sunan an-Nasa'i 4808 
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)."
أَخْبَرَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، قَالَ حَدَّثَنَا وَكِيعٌ، قَالَ حَدَّثَنَا عَلِيُّ بْنُ الْمُبَارَكِ، عَنْ يَحْيَى، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَضَى رَسُولُ اللَّهِ صلى الله عليه وسلم فِي الْمُكَاتَبِ يُقْتَلُ بِدِيَةِ الْحُرِّ عَلَى قَدْرِ مَا أَدَّى ‏.‏
Grade :  Da'if (Darussalam)
Reference : Sunan an-Nasa'i 4808
In-book reference : Book 45, Hadith 103
English translation : Vol. 5, Book 45, Hadith 4812