A Salt Lake resident was duped out of around ₹78 lakh after he installed a “share-trading” app that promised to double his investment within six months, police said.

The police have managed to return more than ₹35 lakh after they tracked down a bank account where a part of the money had been parked, a senior officer of the Bidhannagar commissionerate said.

According to the officer, B. Srivatsa, the victim, had been receiving a series of WhatsApp messages that promised lucrative returns through “trading stocks in the share market”.

“Once Srivatsa showed interest in making investments, he was asked to download an app through a link sent on WhatsApp,” said the officer.

Once he downloaded the app, the scammers presented him with various investment opportunities and multiple accounts for transferring money. They assured him that these funds were being invested in the stock market.

Instructions were also sent through WhatsApp. However, the fraudsters controlled these accounts and the “investments” were nothing more than a ploy to steal Srivatsa’s money, the police said.

“The complainant had transferred a total of ₹77,93,000 to various accounts through the app. As the promised returns did not come, he realised that he had been duped. Whenever he asked the scamsters about it, he was told to keep investing. He did not even get back the principal amount after he asked his ‘share market advisors on the app’ to return it,” said an investigating officer of the Salt Lake cyber crime police station.

According to the officer, the link through which Srivatsa had downloaded the app had led to the installation of a screen-sharing software on his phone that allowed the device’s remote access to the fraudsters.

The police tracked down the internet protocol address of the devices used by gang from the banking transactions and zeroed in on one of the accounts used by them. It had more than ₹35 lakh parked in it.

“We got in touch with the bank and asked them to first freeze the account and then we returned the sum to Srivatsa,” said the officer.

The cops could not make any arrests till Thursday evening.

In May, the Bidhannagar commissionerate issued an advisory against cyber fraud.

Gaurav Sharma, the police commissioner of Bidhannagar, said people “should not download any apps from links sent to them by unknown people” and should refrain from schemes that promise easy money.

“Cyber fraudsters prey on two factors — fear and greed. One should not fall for quick schemes and should refrain from sending money to anyone before checking credentials properly. Cases where people are being told that they have been either summoned to court or their parcels intercepted because they contained narcotics and firearms should contact the police,” Sharma said.

The Bidhannagar commissionerate’s 24X7 cyber crime helpline number is 9038333444.