What is the ruling if the plaintiff in a murder case (the guardian/wali) denies the confession of a second person who claims to be the killer?

Primary text

If a man comes forward claiming responsibility for the killing, but the guardian of the victim denies his statement, the original claim of the guardian against the first defendant remains valid, and the right of *Qasamah* (oath-taking for homicide) is preserved. If the guardian had already accepted blood money (*Diyah*) from the first defendant, he is not obliged to return it. This is based on the view that the guardian's denial validates his original claim and rejects the second claim. No obligation falls upon the confessor because his confession is made to someone who rejects it.