Can the heir of a deceased Muslim establish Qasamah if the heir apostatizes before executing the oath?
Chapter on Qasamah (Oaths regarding murder)
Al-Mughni
Book of Blood-Money (Diyyāt)
Primary text
Abu Bakr and Al-Muzani hold that the heir cannot take the oath, and if he does swear, it is invalid. This ruling is based on the premise that his ownership of his property and rights has ceased due to apostasy, thus leaving him without the right to claim Qasamah. Additionally, since the apostate has committed disbelief, the greatest of sins, he does not deserve the blood of a Muslim through his oath, nor does this oath establish the right to retribution or blood money.
Supporting text
Al-Qadi (the Judge) holds the view, supported by Al-Shafi'i, that the Qasamah should be offered to the apostate heir. If he swears, the blood money becomes obligatory. This is because the entitlement to wealth via Qasamah is a right accrued against others, which is not voided by apostasy, similar to how gaining wealth through valid means is unaffected. His disbelief does not invalidate his oath, as the oath of a disbeliever is valid when presented in disputes; if he swears, retribution or blood money is established. If he returns to Islam, the right is his; if he dies while apostate, the property becomes Fai'.