Can a company take legal action against an employee?

Someone among our employees has done fraud with us. He did money laundering of 50 to 60 lakhs and now he's poaching our clients. He also opened his own company in the name of someone else and working for that new company that is his own company. at that time he was getting salary from us. He was officially our employee but he was working for his own company. Now when we terminated after getting to know these frauds and all, we terminated him and mailed him that we will take a legal action. now he is threatening us in the name of our family and abusing us and saying that you cannot do anything with me or you cannot even touch my hair. What should we do? We are feeling trapped. We are broke because of his money laundering. What should we do?