What are the sayings of the jurists and the different schools of thought regarding killing, especially in cases of physical altercations that lead to death, given the difficulty of determining intent (intentional or accidental) due to the nature of modern weapons, and especially if the perpetrator admits to the incident but denies intentionality?

Injustice is forbidden both in word and deed, as stated in the Hadith (definition) Qudsi: "O My servants, I have forbidden injustice for Myself and have made it forbidden amongst you, so do not oppress one another," and "Injustice will be darknesses on the Day of Resurrection." The best of Muslims is he from whose tongue and hand other Muslims are safe. The oppressed is permitted to defend himself commensurate with the injustice, without aggression. However, forgiveness and pardon are preferable, as Allah Almighty says: "And the retribution for an evil act is an evil act equivalent to it. But whoever pardons and makes reconciliation - his reward is [due] from Allah. Indeed, He does not like wrongdoers. And whoever avenges himself after he has been wronged - those have not upon them any cause [for blame]." If self-defense leads to the death of the oppressor, the intention varies depending on the situation, and Allah knows what is in the hearts. Islamic judiciary deals with evidence and circumstantial indicators, and jurists have differentiated between intentional killing, accidental killing, and semi-intentional killing.