Joint Commissioner (Crime) Murlidhar Sharma said the fradulant withdrawals were deing done from Delhi.
"Our team has reached Delhi and started its work. We have got some CCTV footage. We are looking into them," said Sharma, who announced that two cases have been registered in Jadavpur and Charu Market police stations by clubbing all the complaints.
Last year, fraudsters had withdrawn large amounts of money by attaching skimming devices to some ATMS in south Kolkata areas such as Gariahat, Lake Gardens and Jadavpur. The police had then arrested a gang of Romanians for the crime, who are still in jail.
Sharma said in the latest cases also, preliminary enquiries point towards a similar happening.
As a preventive measure, the city police top brass have decided that motor cycle patrol teams from every police station will check the ATMs, especially those without any security guard, twice daily so that "nobody can attach any skimming device".
"We have also spoken to bank officials, so that we can return the money to the affected depositors fast," he said.
Sharma also advised AATM card holders to change their pin numbers at least once every six months.
He also said that some banks, including the SBI, have introduced a feature in their apps by which customers can activate their ATMs just before using them, and deactivate them after using it.
"If you take such steps, you won't have to face harassment," he added.