Musannaf Ibn Abi Shayba 28:695

'Abdullah ibn Idris narrated to us, from Muhammad ibn Ishaq, from Yazid—meaning ibn Abi Habib—that Abu Bakr sent 'Ikrimah ibn Abi Jahl as a reinforcement for al-Muhajir ibn Abi Umayyah and Ziyad ibn Labid al-Shami. They arrived at the people while [the victory] had already been opened for them, and the people were [still] in their blood. He said: So they made them partners in their spoils.