Is the person who has had retribution sought against them obliged to prove their defense to avoid retribution, and in the absence of evidence, is retribution carried out against them according to Sharia, and can they do anything to avoid it?

If someone kills another and claims it was in self-defense, then if the slain person's guardian (wali) believes him, so be it. Otherwise, he must provide evidence for his claim. If no evidence is found, the slain person's guardian can demand retribution (qisas), because the killing is confirmed and his claim contradicts the apparent truth.

However, there might be circumstantial evidence that corroborates the claim of assault or raises doubt about the eligibility for qisas, which the judge would consider. For example: if the slain person was known for evil or corruption, or if there was animosity between him and the killer, or if the killing occurred in a place where evidence cannot be established.

- Hanafi school: If there is no evidence, and the slain person was not known for evil, then qisas is applied to the killer. But if he was known for evil and theft, there is no qisas, and blood money (diyah) is due. - Maliki school: Qisas is applied to him if there is no evidence, unless the killing occurred in a deserted place, in which case his statement is accepted with his oath. - Shafi'i school: His statement is not accepted unless there is evidence indicating that the slain person entered his house brandishing a weapon. It is sufficient if the slain person was known for corruption or if there was animosity between them. - Hanbali school: His statement is not accepted except with evidence; otherwise, qisas is applied, regardless of whether the slain person was known for corruption or not. If the evidence testifies that he attacked him with a drawn weapon, his blood is considered forfeited.

This applies to judicial rulings. As for the matter between the killer and his Lord, if he indeed killed him in self-defense, there is no blame on him, and no sin if he flees from qisas; for whoever is killed defending his property is a martyr, and whoever kills an aggressor is in the Fire.