What is the ruling of Islamic law on a killer who assaulted the victim's home and caused her death?

Kin and relatives should strive for reconciliation and forgiveness to prevent problems from escalating among them. Jurists have urged reconciliation between disputants, and it is obligatory if the problem is feared to worsen. The killer has committed a great sin, and Allah has threatened him with Hellfire. Allah has legislated for the guardian of the blood (victim's heir) to demand retribution (qisas) from the ruler. It is not permissible for the guardian of the blood to kill the murderer without referring to the ruler; rather, he must refer the matter to the Sharia (definition) courts.