What is the ruling regarding someone who regrets renting their house to a person who harmed those around him, and whose stay has ended and he has returned to his country, and the landlord does not know his address? Is informing others in an attempt to find him considered publicizing a sin? And what should he do if he cannot find him to repent for the rights of those whom he wronged?

Repentance from sins related to the rights of people requires restoring those rights or seeking forgiveness from their owners. However, if this is impossible due to not knowing them, or being unable to reach them, or being incapable of restoring the rights, then Allah will take care of it if He knows the sincerity of the repentant person and their eagerness to fulfill their obligations. The repentant person should also increase in good deeds and seek forgiveness for the owners of the rights. As for informing others about what a man has done to seek help, backbiting (gheebah) is originally forbidden, except for a valid legitimate purpose, such as warning Muslims from evil or seeking assistance in changing an evil.