How to legally recover Stridhan?

My sister, Mrs. Veena Pratap Singh Badiger, got married on 26/12/2021 and passed away on 18/09/2024. During her lifetime, she filed a DV/criminal complaint against her husband and in-laws. After her death, civil proceedings were closed, but the criminal case is still pending. Her streedhan articles (silver, pooja items, personal belongings, etc.) are still in possession of her husband and relatives. Some items are allegedly kept in a locker/safe, and we have video evidence of the same. Despite repeated requests, they allegedly demanded withdrawal of the criminal case before returning the streedhan. I filed a KSP online complaint and later sent a legal notice via RPAD on behalf of my mother (legal heir). The notice was delivered, but no reply has been received. Please advise on the proper legal remedy, jurisdiction, civil or criminal action, and required documents/evidence.