Police asking for witness after filing of F.I.R

My father went to ATM on 31st March for withdrawing money. Because the ATM wasn't working a person offered his help and he took my father ATM and swiped it inside the ATM. After swiping my father's debit card inside the machine he handed over the debit card to my father. But my father wasnt able to notice that it was a different expired ATM. My father hid his debit card pin while entering but he somehow figured out the password.After only reaching home did my father noticed that there was message of withdrawal of Rs.35000 in his phone. And just then my father called up the Customer care of Bank to block the debit card. Also the theif transferred more Rs.35000 into his account whose message didn't arrive in my fathers phone. Now after filing F.I.R with section 419 against the culprit no investigation has been initiated by the police and police have asked for Aadhar ID of two people as witness. I wanted to know if police can demand witness to this incident at such early stage.