Sahih Bukhari Volume 7, Book 67, Hadith Number 385.

Narrated By ‘Adi bin Hatim : I asked Allah’s Apostle about the Mi’rad. He said, “If you hit the game with its sharp edge, eat it, but if the Mi’rad hits the game with its shaft with a hit by its broad side do not eat it, for it has been beaten to death with a piece of wood. (i.e. unlawful).” I asked, “If I let loose my trained hound after a game?” He said, “If you let loose your trained hound after game, and mention the name of Allah, then you can eat.” I said, “If the hound eats of the game?” He said “Then you should not eat of it, for the hound has hunted the game for itself and not for you.” I said, “Sometimes I send my hound and then I find some other hound with it?” He said “Don’t eat the game, as you have mentioned the Name of Allah on your dog only and not on the other.”