Abdullah ibn Atik was a companion of Muhammad. He participated in the Expedition of 'Abdullah ibn 'Atik where he successfully assassinated Sallam ibn Abu al-Huqayq. Where he led a group of men from the Banu Khazraj tribe.
He was killed in the Battle of Yamama.
Abu Rafi's assassination at the hands of Abdullah ibn Atik is mentioned in many Sunni Hadith:
Abu Rafi's assassination is mentioned in: Sahih al-Bukhari, 5:59:370, Sahih al-Bukhari, 5:59:371, Sahih al-Bukhari, 5:59:372 and many more.