Sahih Bukhari Volume 007, Book 067, Hadith Number 394.
Narrated By 'Adi bin Hatim : I said, "O Allah's Apostle! I let loose my hound after a game and mention Allah's Name on sending it." The Prophet said, "If you let loose your hound after a game and you mention Allah's Name on sending it and the hound catches and kills the game and eats of it, then you should not eat of it, for it has killed it for itself." I said, "Sometimes when I send my hound after a game, I find another hound along with it and I do not know which of them has caught the game." He said, "You must not eat of it because you have not mentioned, the Name of Allah except on sending your own hound, and you did not mention it on the other hound." Then I asked him about the game hunted with a Mi'rad (i.e. a sharp edged piece of wood or a piece of wood provided with a sharp piece of iron used for hunting). He said, "If the game is killed with its sharp edge, you can eat of it, but if it is killed by its broad side (shaft), you cannot eat of it, for then it is like an animal beaten to death with a piece of wood."