What is the ruling of Islamic law regarding informing about an incident of accusation that occurred between two people when asked about it?

The fundamental principle is to conceal and not inform anyone about accusations that arise among people, for whoever conceals [the faults of] a Muslim, Allah will conceal his [faults] on the Day of Resurrection. It is commendable to keep secret any evil spoken about a person if there is no benefit in disclosing it.