Eloped after taking money

Hi, I am a IT professional working in Saudi Arabia. One of my relative asked for some financial help six month ago who lives in Mumbai. I helped him with amount of Rs 50,000. He promised me that he will return the amount within a month time. When a month passed; I called him up and he told me that he will drop the amount in my account within 2-3 days. After passing 2-3 days again I called him and he told me that I am in bank to drop your money. When the day passed and I didn't receive the amount in in my account; I called up again but he didn't pick up the phone. Since then I am trying to trap him but all in vain. It has passed six months now and I am unable to trace him. My problem is that I don't have his residence address in Mumbai. Only I have his mobile number. His number is active but I call from Saudi Arabia regularly but he doesn't pick up the call. Even I asked one of my friend in Mumbai to call the number locally but he doesn't pick the call at all from unknown number. Now I don't any option except take a legal action against him. I want suggestions in this regard; how can I proceed for this and what is the method to trap him legally. Thanks Aftab Khan E-mail: aftnad@yahoo.com