Caught cousin sister sending her nude pic to her Boy Friend

Dear Sir/Madam, Few months back one of my friend Nagaraj had caught her cousin sister Shika red handed sending her nude pic to her Boy Friend. He did not inform it to her parents and counselled her on the same. When she did not agree to his counselling he thought of intimating to her parents. So he informed the same thing to his cousin brother Manju (he sent Shikha's Pic to Manju) after taking the pics from shikha's mobile by bluetooth. Cousin brother Manju informed the same to his mother and they wanted to convey the same to shika's parents. So they called Shika's brother danush confidentially and narrated him the incident. Danush was shocked and wanted to convey the message to his parents. Dhanush & manju together went to Shika's home and told the whole incident. As it was a matter of family respect, even though they knew her daughter was at fault. They wanted to defend their daughter. They felt insulted by the act of their daughter. Now they are wanting take revenge on Nagaraj. Hence nagaraj , Dhanush and another cousin Manoj are threatened. Shikas parents want to hide their daughter. hence they are making arrangements to proceed legally by making false statements like "Harassment & check bounce" What can Nagaraj and his brothers do now?