Abu Bakr bin Amr bin Hazm narrates from his father, from his grandfather, that the Messenger of Allah (peace be upon him) wrote a document for the people of Yemen, and in that letter it was stated: "Whoever kills a Muslim without reason, and the murder is proven against him by witnesses, then retribution (qisas) is obligatory upon him (i.e., he will be punished in kind), unless the heirs of the slain are pleased (i.e., they forgive him)."
Imam Darimi (may Allah have mercy on him) said: The meaning of «اعتبط» is to kill without any excuse.