Illegally Detaining a Serving Govt Servant without any proof

My father who's 56 years old was last night detained by a patrolling battalion of Bihar Excise Department Police throwing allegations that he was involved in drinking liquor. The proof that they talked about was a drone video about 50m away from the place where my father stopped to have a cup of tea. Nothing was found in possession. Neither he was drunk nor there was any plan. He himself is a government servant and was returning to home after duty and the excise Police didn't listen any to his words. They abused him and my mother on call along with manhandling him. They brought him to Excise Department Office locked the gate for entire night they didn't let us have any contact with our father. Snatched his phone and even beat him a few times. Next morning they released him saying they didn't have proof. We want to do anything to file a case against this behaviour of Excise Police. We are willing to approach even the most Superior Court to have a case about this violation of Rights.