What is the ruling regarding retribution (Qisas) when the killer of a person is subsequently killed by someone other than the legitimate heir (Wali al-Dam)?
General Chapter
Al-Mughni
Book of Wounds
Primary text
Retribution (Qisas) is obligatory upon the second killer for killing the first killer. Furthermore, the heirs of the first victim are entitled to blood money (Diyah) from the estate of the first perpetrator. This is the position held by Al-Shafi'i. The evidence for the obligation of Qisas is that the life of the second victim was not unconditionally forfeit, nor was it permissible for someone other than the legitimate heir to kill him, thus necessitating Qisas for his killing, similar to a debt obligation. The evidence for the Diyah being due from the first perpetrator's estate is that when Qisas becomes impossible due to death, pardon by some partners, or the emergence of an impediment, Diyah becomes obligatory.
Supporting text
Al-Hasan and Malik hold that the second killer is executed, but the blood claim of the first victim is voided because its proper venue has passed, similar to a slave committing the initial crime. Al-Qatadah and Abu Hashim narrated that no Qisas is due upon the second killer because he killed a person whose life was permissible to take, making retribution inapplicable, similar to the case of the married adulterer.