My elder-sister had purchased some goods from a shop by using ICICI ATM Debit card in Bhubaneswar on 08-06-2012. She came back to Bangalore from Bhubaneswar on 09-06-2012 in evening flight. After reaching Bangalore, she checked her ICICI savings account balance from internet and shocked to notice that someone has withdrawn Rs 25000 from the ATM located Bhubaneswar in the evening of 09-06-2012 when actually she was in Bhubaneswar airport carrying her ATM card in her purse. She never handed over the ATM card to anyone else nor disclose the PIN number to others. How someone can withdraw the money without ATM card and PIN number from an ATM counter.
She has already blocked the ATM card and submitted a written complaint to the ICICI bank branch along with FIR.
Please suggest what legal action should be taken in this case.