Dear Mr. Singh,
First of all you would need to collect all such documents which have been forged and fabricated.
Secondly, if the employee is in breach of the terms and conditions of the appointment letter, you need to send a legal notice to the said employee, for "Specific performance of the Contract", with a copy of the said letter being sent to his current employers. You can also file a Civil Case of Specific performance of a contract, or for damages for breach of contract.
Thirdly, you can file a FIR with the local police station for fraud and forgery of Company documents, under the provisions of the Indian Penal Code. And if the Company wants to handle the forgery case themselves, they can file a private compliant with any of the Magistrate Courts, against the said person.
I would suggest that you engage a legal practitioner, specialising in criminla law, to help you with the formalities.
Ashish.
