When Ameerul Momineen (a.s.) was struck down by Abdul Rahman ibne Muljim (l.a.), Jibrail (a.s.) was heard announcing between the skies and the earth in a voice heard by every wakeful person – By Allah, the pillars of guidance have been felled, by Allah the stars of the sky and the standards of piety have been obliterated. By Allah, the reliable rope of Allah has been severed. Muhammad al-Mustafa’s (s.a.w.a.) cousin has been killed, the chosen successor has been killed, Ali al-Murtaza has been killed. By Allah, the chief of successors has been killed. The most wretched one has killed him.
Behaar al-Anwaar v 42 p 282, 285, 286