Married sex pervert and blackmailer

There is married a guy living in Mumbai pretending to be single, he sends his own naked pictures to foreigner girls living overseas, he gets them to send their naked pictures and he threatens to release the pictures. Email complaint to Women's commission led no where as they simply asked to come to india to personally register the complaint. Email complaint to police also resulted in police asking the foreigner to go to the police in their own country (outside India) even though the perpetrator is committing these crimes from India. 1. What are the ways a foreigner living overseas can use to ensure action is taken by the India police, court or other authorities? 2. What are the ways a foreigner living overseas can use while REMAINING ANONYMOUS (e.g. ask authorities to raid the culprit and collect evidence) to ensure action is taken by the India police, court or other authorities? e.g. how to make courts, police or authorities act on anonymous overseas complaint on SUO MUTO or any other basis? 3. What is the most pragmatic way to make the authorities in India take action, these might not be legal suggestion but rather procedural suggestions as to how to use the system e.g. tweet to India's PM or foreign minister or anonymous letter to high court judge (for them to take suo muto action) or to the speaker of assembly (for them to take up in the judicial law and order committee) - what is the feasibility and probability of these working, how to maximize the chances of success, ? Remember, all based on anonymous complaint from overseas, via email. This is not frivolous complaint to harass or seek revenge, but a genuine complaint, where there as good reasons to remain anonymous (police leaking information to media or culprit, potential public stigmatization or blow back and retaliation from the culprit).