The incident was reported on Saturday night after the HDFC Bank learnt about the missing amount from one of its ATMs installed on Vikas Marg in east Delhi.
"A case under charges of stealing has been registered. We suspect over the role of bank employees and other connected people behind the incident as the missing amount was taken out of the ATM without damaging the machine," Deputy Commissioner of Police Omvir Singh told IANS.
As some nuts and bolts of the machine were found loose during investigation, it gives a clear indication towards staff members of the bank, the officer said.
"Without knowing password or other internal information about the machine, no one can manage to open it easily. There are various ways to rob any ATM machine," he said.
The criminals also changed the position of the CCTV camera to avoid any recording, said the officer, hoping to solve the case very soon.