What is the effect of the perishing of bequeathed slaves before or after the testator's death?

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If all the testator's slaves perish or are killed before his death, the bequest is nullified because it only becomes binding upon death, and there are no slaves then. If they perish after his death without negligence on the part of the heirs, the bequest is nullified because the estate held by the heirs is not guaranteed (ghair madhmun) as it came into their possession without their agency. If a third party kills them, the legatee is entitled to the value of one slave, based on the differing opinions regarding what the legatee is entitled to while the testator was alive.