Hawzah News Agency – If a person kills one of his relatives intentionally (ʿamdan) and unjustly, he does not inherit from him. However, if the killing was justified – for example, it was a retributory punishment (qiṣāṣ) [as sanctioned by a judge], or the legal execution of a punishment, or it was in self-defence – then he does inherit from him. The same applies if the killing was due to some error. For example, if he threw a stone in the air and by chance it hit one of his relatives and killed him, he inherits from him; however, he does not inherit from the blood money (diyah) that his relatives pay for the killing. As for manslaughter – i.e. killing someone, without intending to, by intentionally doing something to the person that would not usually result in death – this does not prevent him from inheriting.

Source: https://www.sistani.org/english/book/48/