Expiation due for mistakenly killing someone with a gunshot and paying Diyah

Q: A man unintentionally shot another to death and paid the Diyah (blood money). (Part No. 21; Page No. 274) What expiations he should make? May Allah have mercy upon you.

A: If the reality was as you mentioned, this man should emancipate a believing slave; and if he is unable to do that, he should fast for two consecutive months, as stated in the Qur'an.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.