Musnad Ahmad 790:127

'Abd al-Samad narrated to us, my father narrated to us, Yunus narrated to us, from Ibn Sirin, from 'Imran ibn Husayn, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, your brother, the Negus, has died, so stand up and pray over him." He said: So we formed rows and prayed over him just as you pray over the dead. 'Affan narrated to us, Bishr ibn al-Mufaddal narrated to us, Yunus ibn 'Ubayd narrated to us, from Muhammad ibn Sirin, from Abu al-Muhallab, from 'Imran ibn Husayn, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, your brother, the Negus, has died, so stand up and pray over him." He said: So we stood up and formed rows for him just as we form rows for the dead, and we prayed over him just as we pray over the dead.