Co-founder diverted company funds for personal use, how can I take legal action?

I started a startup in Hyderabad with a friend. I've discovered that he has been siphoning funds from our business account for his personal expenses, totaling about ₹15 lakhs. This has severely affected our operations and trust. I feel betrayed and don't know how to handle this legally. What steps can I take to address this situation and recover the money?