From Sahih Bukhari (Hadith 4762):
Narrated Al-Qasim bin Abi Bazza:That he asked Sa`id bin Jubair, "Is there any repentance of the one who has murdered a believer intentionally?" Then I recited to him:-- "Nor kill such life as Allah has forbidden except for a just cause." Sa`id said, "I recited this very Verse before Ibn `Abbas as you have recited it before me. Ibn `Abbas said, 'This Verse was revealed in Mecca and it has been abrogated by a Verse in Surat-An-Nisa which was later revealed in Medina
Reference: Bukhari 4762