Quran

وَلَا تَقۡتُلُواْ ٱلنَّفۡسَ ٱلَّتِي حَرَّمَ ٱللَّهُ إِلَّا بِٱلۡحَقِّۗ وَمَن قُتِلَ مَظۡلُومٗا فَقَدۡ جَعَلۡنَا لِوَلِيِّهِۦ سُلۡطَٰنٗا فَلَا يُسۡرِف فِّي ٱلۡقَتۡلِۖ إِنَّهُۥ كَانَ مَنصُورٗا

And do not kill the soul which Allah has forbidden, except by right. And whoever is killed unjustly - We have given his heir authority, but let him not exceed limits in [the matter of] taking life. Indeed, he has been supported [by the law]