Sahih Bukhari Volume 6, Book 60, Hadith Number 286.

Narrated By Said bin Jubair : The people of Kufa differed as regards the killing of a believer so I entered upon Ibn ‘Abbas (and asked him) about that. Ibn ‘Abbas said, “The Verse (in Surat-An-Nisa’, 4:93) was the last thing revealed in this respect and nothing cancelled its validity.”