What is the maximum retribution established through Qasamah?
Chapter on Qasamah (Oaths regarding murder)
Al-Mughni
Book of Blood-Money (Diyyāt)
Primary text
The established ruling is that Qasamah only entitles one to retribution for a single killing. This position is held by Al-Zuhri, Malik, and some of Al-Shafi'i's companions. The evidence for this is the Prophet's statement: 'Fifty of you shall swear concerning one of them, and he will be handed over to you by his neck (or life).' This specifically restricted Qasamah to one individual. Additionally, since Qasamah is a weak evidence that deviates from the original principle concerning a single killing, its application should be limited to that instance, preserving the original principle for cases beyond it.
Supporting text
Some scholars maintain that Qasamah can establish retribution against a group because it is evidence establishing retribution (qawad), thus being equal to regular testimony where both one and a group are treated equally. This aligns with the view of Abu Thawr.