Wifes side doing unlawful act to collect evidence, harming my brother

Dear Sir, i have already divorced my wife in year 2015. case of child custody. going in court. recently we have filed some additional documents of her adultery in court . after which couple of rogue elements have started visiting my elder brothers shop, and threatned him. later on after a few days. one person barged in to the shop posing as a customer, and started clicking my brothers photos using his mobile phone. this came in my brothers notice, he immd confrontedmy brother asked the person to accompany with him to the station, the person ran away leaving his phone. we immd rushed to the police station and gave a written complaint, and the same was entered in GD diary. number of the brother of my ex wifes number, as we told him he is the person.WHAT ARE THE SECTIONS APPLICABLE FOR THIS OFFENSE.who all can be booked.can i keep the phone with me until the case is booked or are their any chance of them booking any case since the phone is with me as proof.