In 625 C.E., one of the chiefs of the tribe of Kilab, Abu Bara Aamir requested the Holy Prophet to send Muslim missionaries to propagate Islam among the tribe. The Holy Prophet sent seventy Muslim missionaries with the chief. The party halted at a place Bir Maunah, and sent a Muslim, Haram b Mathan, along with the letter of the Holy Prophet to Aamir b Tufail, the principal chief of the tribe of Kilab. Aamir b Tufail killed Haram, and marched with an army to Bir Maunah. He assassinated all the Muslim missionaries except one, Amr b. Umayyah by name. Aamir b Tufail released Amr b Umayyah according to his mother's vow to free a slave. On his way back to Madina, Amr b Umayyah killed two persons belonging to the tribe of Banu Amar considering them to be enemies. As a matter of fact, the Holy Prophet had given the tribe amnesty. When the case was brought to the notice of Holy Prophet, he agreed to pay indemnity to the tribe for its murdered persons.