Six “SIM boxes” — devices that can make international calls appear as local ones and are often used for fraud — were seized from a house in North 24-Parganas on Wednesday morning. Police said the setup was
allegedly used to cheat a senior citizen of ₹3.01 crore.

Investigators suspect a Malaysian national to be the mastermind behind the operation.

Arpan Sikdar, 24, a resident of Maniktala, was arrested on Wednesday for allegedly operating the SIM boxes. The devices had been camouflaged inside a dustbin at his girlfriend’s house in Ashokenagar, the police said.

“While interrogating Arpan Sikdar, we found contact details of a Malaysian national who had provided the SIM boxes to his handler. We are looking
for both the Indian handler and the
foreign national,” said a senior officer.

The seized SIM boxes contained hundreds of slots. The police also recovered 130 pre-activated SIM cards.

A SIM box is used to route Voice over Internet Protocol (VoIP) calls in a way that masks their origin, making international calls appear domestic and helping fraudsters evade law enforcement agencies.

A senior officer said investigators were not ruling out the possibility that the fraudulent calls originated from Malaysia and were routed through
the SIM boxes.

Joint commissioner (crime) of Kolkata Police, Rupesh Kumar, said the arrest followed earlier detentions in connection with an online fraud case.

In October last year, an elderly electrical engineer running a business in electrical goods was duped through a “digital arrest” scam.

The victim was coerced into transferring ₹3.01 crore into multiple accounts by fraudsters posing as officials of the ED and the CBI. They claimed illegal substances had been booked in his name in a courier, triggering a central agency probe, Kumar said.

The elderly man and his wife
were kept under video surveillance
for four days and forced to transfer
their savings, with assurances that
the money would be returned after
the “probe” concluded.

The fraud came to light when the family realised they had been deceived and approached the police.

Kolkata Police’s cyber cell began investigating and traced links to a Bangladeshi national. By the time officers tracked him down, he was already in the custody of Bidhannagar police.

A few months ago, Bidhannagar police had arrested the Bangladeshi national, Sheikh Abir, for allegedly operating multiple SIM boxes in Salt Lake and New Town.

Kolkata Police later took him into custody after finding links to the case and also arrested another man from Collin Street.

During the investigation, a laptop was seized and subjected to forensic imaging, data extraction and artefact analysis. “Examination of browser history and network logs revealed consistent access to a SIM box from which multiple calls were generated,” an officer said. This led investigators to Sikdar.

Kumar said the police had earlier seized 12 SIM boxes and 2,000 pre-activated
SIM cards from the accused duo.