1) Please note that in title, I have used word "Prevent" and not used word "Prosecute".
The first rule of battles is not to start fight without knowing strength of enemy.
Behind anonymous or fake handles, you do not know who is there. It can be a mouse or a tiger.
If a criminal mentality person is using fake handle to abuse, then you must know that it is not your job to prosecute criminals.
There is no law in India to protect complainants and witnesses.
Avoid taking blind risks.
2) Use simple preventive measures like blocking and reporting to social media's grievance site.
They will probably check and suspend the fake account.
3) If abuse is such that you may have to initiate legal action, then first make "emails to self" of the offending posts, tweets or updates.
This way you will have digital evidence with you. Or take screen shots. Whatever you think fit. But collect the evidence.
4) Cyber cell, etc agencies are still new in India. They may or may not have enough manpower to deal with your complaint effectively.
But still if you think you must initiate police actions, you can search their addresses from website and can register complaint.
5) And what if they do not take any action?
Then you need advice of a lawyer. He may advice you about filing a criminal complaint in court of a Magistrate or can advice you to file civil suit for preventing abuse and / or to seek damages and/ or to seek injunction or stay orders against website also.
6) Remember first rule of battles. Do not start battles without first assessing your own strength.
Haresh Raichura (c)
22/5/2016