Q: A man killed another person unintentionally in a car accident, and a Diyah (blood money) of one hundred thousand Riyal was collected for him. Two years later,
the court judged that only half of the Diyah had to be paid
because both the man who committed the accident and the dead person were mistaken. Does the other half of the money that was collected become the right of the man who committed the accident?
(Part No. 21; Page No. 262
If reality is exactly as what you have mentioned in the question, and you know the persons who gave this amount, it will be Wajib (obligatory) on you to repay them the remaining amount. However, if you do not know them, and there is somebody else who is burdened by a Diyah that they can not afford; it will be Wajib on you to give them this sum through the court. Finally, if neither of the two previous channels is applicable; you will have to give the sum as Sadaqah (voluntary charity) to some poor people, for the construction of Masjids (mosques), or in any other charitable ways of disposition on behalf of the people who donated the money that was originally for Diyah.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.