Hard disc issue

My brother married to a girl 9 Dec 2020. After some time we realized that The girl and her family members are of criminal nature. The girl works at beauro of Indian standard ( Bis) and my brother is a patent officer. One day when my brother was away the girl copied my brother's laptop data and phone data to her office laptop. She also opened his Gmail account. When my brother got to know about this he broke her laptop. Now she has filled a complaint against my brother that he has stolen her hard disc. The police official calling us again and again and touring my brother. Several times when we go to police station neither the police officer not the girl come there. And next day police officer say that he had emergency duty pervious day and we have to come police station again. We have requested a copy of complaint but the police officials is not showing that. We don't have any hard disc. But the police officer is threating us that BIS is sending email to him that the hard disc has sensitive data from public, and we will be in big trouble if we don't return the hard disc. What should we do?