Sahih Bukhari
Holding Fast to the Quran and Sunnah
Volume: 009 / Book Number: 092 / Hadith Number: 423
Narrated 'Abdullah:
The Prophet said, "None is killed unjustly, but the first son of Adam will have a part of its burden." Sufyan said, "..a part of its blood because he was the first to establish the tradition of murdering"