Ibn Sirin said: Sa'd (may Allah be pleased with him) was urinating while standing when he suddenly leaned over and died; the jinn had killed him, and they said: "We have killed the chief of al-Khazraj, Sa'd bin Ubadah, and shot him with two arrows that did not miss his heart."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5340