Musnad Ahmad 795:2

'Affan narrated to us, Hammam narrated to us, Qatadah narrated to us, from al-Hasan, from Jun ibn Qatadah, from Salamah ibn al-Muhabbaq, that the Prophet, peace and blessings of Allah be upon him, came upon a house and in front of it was a hanging water skin. The Prophet, peace and blessings of Allah be upon him, asked for a drink. They said: "It is dead (i.e., from an animal that died without slaughter)." He said: "Its tanning is its slaughter."