The accused allegedly targeted 4,727 people across India.
Seven persons including three Nigerians have been arrested by city police for hacking into over 2,000 bank accounts and transferring crores of rupees after creating a fake webpage of the Income Tax Department.
The accused lured victims across the country by promising income tax (IT) refunds, and for the first time arrests have been made in these cases, the local cyber crime cell claimed.
The accused were arrested from Mumbai Wednesday and brought here, said assistant commissioner of police (cyber crime) J M Yadav.
The accused allegedly targeted 4,727 people across India, of which over 2,500 were duped of crores of rupees.
There were at least 57 unsolved cases of such frauds in the country, ACP Yadav added.
Ahmedabad police started a probe after Tejas Shah, a city-based doctor, filed a complaint that over Rs 2 lakh were transferred from his account on June 22 last year.
Explaining the accused's modus operandi, ACP Yadav said, "They first sent a web link to the victim through SMS, promising to get IT refund. When the victim clicked the link, he was directed to a "phishing'' page (a fake webpage) resembling the webpage of the IT Department.
"After the victim filled in the name of his bank, he was directed to a fake webpage of the bank where he was asked to fill in all the details of his bank account," the ACP said.
"The victim was then sent a link of a mobile app as the last stage of getting refund, which, when downloaded, enabled the fraudsters to hack into the victim's mobile phone, which was then used to obtain the password for net banking.
Then money was transferred from his account to a dummy account," ACP Yadav said.
The money thus stolen from the bank account was converted into bitcoins (a digital currency which most governments do not recognise) and sent abroad, the officer added.
The accused were identified as Idrish D' Costa, Sinedu Christopher, Ifaain Odhu (all Nigerians); Irfan A Dehmukh, Tabiz Deshmukh, Rajesh Gaikwad and Nizamuddin Shaikh.