A call from the “RBI” saying all bank cards will be blocked in two hours or an alert call from a telecom operator that a SIM card is about to be blocked can leave one poorer by several lakhs of rupees.

Police said swindlers are using an interactive voice response system to make the calls sound genuine and win the confidence of their targets.

Once a target gets hooked, he is told about the problem he would face if he does not follow what is being told over the phone.

The conversation ultimately leads to the threat of “digital arrest”, which prompts the person targeted to share the banking details.

Police officers have repeatedly clarified that there is no such thing as “digital arrest”, which has come to mean that an accused can be arrested online.

“For the swindlers, the threat of ‘digital arrest’ is an effective weapon to pressure their targets to part with money,” an officer said.

Recently, a retired judge in Chandernagore lost Rs 32 lakh to escape “digital arrest” after being told that his bank account had been used for money laundering and he would be arrested unless he shared the details of all his bank accounts.

“The swindlers are coming up with new ways to convince people. For example, the threat to block SIM cards or freeze bank accounts is the most common way to victimise people. Most people get scared after listening to such threats,” said a senior officer in the cybercrime cell of Kolkata Police.

“The next step is to convince the victim to talk to the swindlers, who pose as policemen and pretend they are only interested in helping him evade arrest. At this point the racketeers threaten ‘digital arrest’, scaring the victim into sharing his banking details.”

A text message claiming to be from a private bank recently informed a Calcuttan that the reward points credited to his account would lapse unless he clicked a link provided in the message.

The recipient of the message, a resident of Kasba, does not have an account in the bank.

“Many would have been tempted to click the fraudulent link. But this recipient did not as he does not have an account in the private bank,” an officer said.

“It is very important to remain calm and make a logical decision. Swindlers try to lure the target with money or rewards or scare them with the threat of arrest. Many fall into the trap and end up sharing their banking details with the racket or downloading an app that would allow the swindlers remote access to their devices,” the officer said.