Abu Dawud Book 34, Hadith Number 4524.

Chapter : On a person who is killed among his people and his slayer is not known.

Narated By N/A : Tawus in his version said: If anyone is killed. Ibn ‘Ubaid in his version said: The Apostle of Allah (may peace be upon him) said: If anyone is killed in error (blind-ly) when people are throwing stones, or by beating with whips, or striking with a stick, it is accidental and the compensation for accidental death is due. But if anyone is killed deliberately, retaliation is due. Ibn ‘Ubaid said in his version: Retaliation of the man is due. The agreed version then goes: If anyone comes in (between the two parties) to prevent it, Allah’s curse and anger will rest on him, and neither supererogatory nor obligatory acts will be accepted from him. The version of the tradition of Sufyan is more perfect.