1. Since the Police is investigating and two of her family has been arrested , find out from the police what details they have.
2. if they caught the two in custody the property and bank accounts can be sealed and seized,and if they are charged under economic offences and Tamilnadu chitfund act 1961, surely police can trace the lady through them.
3. From your side make sure that the case is strong and follow it up with the police, as there is all the chances of the parties influence the police.
4. Since you do not have any documents to prove that it is difficult to file an recovery suit against them.
5. How was the payment made was it cash or in cheque, if the payments made by cheque you have some proof of the remittance which will help you in a civil suit.
6. If the criminal case is taken ahead , there is chance of the money can be recovered.
7.There is no safe option other than legal option and it is not advisable to take the law in your hand,