General ruling: Seizing or using the property of another person without their permission is considered a usurpation (ghasb). Therefore, it is obligatory for the usurper to repent to God and to restore or reimburse what they have usurped to the rightful owner through the following steps:
First step: Restore the usurped property or pay its monetary equivalent directly to the rightful owner, or to their inheritors if the owner is deceased. If this is not possible for any reason, one must resort to the following step(s):
Second step: Restore the usurped property or pay its monetary equivalent indirectly to its rightful owner, or to their inheritors if the owner is deceased. An example could be something like anonymously mailing a cashier’s check. If this is not possible for any reason, one must resort to the following step:
Third step: Give the usurped amount to the poor as alms (sadaqah) on behalf of its owner. However, based on obligatory precaution, this should be done after receiving permission from the supreme religious authority (marja) or his authorized representative. If a person is unable to pay the amount in full or even partially, they must pay what they are capable of and entrust another person to fulfill the rest in the event of their death.
*If the usurped amount is unknown, one is only required to pay the minimum amount that they are certain of. For example, if the exact amount is unknown, and believed to be either $100 or $150, it is enough to pay $100. However, it is advisable to pay more to ensure that the actual amount is paid in full.