From Sahih Bukhari (Hadith 3971):
Narrated `Abdur-Rahman bin `Auf:"I had an agreement with Umaiya bin Khalaf (that he would look after my relatives and property in Mecca, and I would look after his relatives and property in Medina)." `Abdur-Rahman then mentioned the killing of Umaiya and his son on the day of Badr, and Bilal said, "Woe to me if Umaiya remains safe (i.e. alive)
Reference: Bukhari 3971