Twelve persons, including “directors” of three call centres in Baguiati that were allegedly duping people, were arrested after Salt Lake police conducted raids on Wednesday night.

The arrested persons would allegedly promise people high returns if they let them use their land or rooftops to erect cellphone towers of reputable network providers, an officer of the Bidhannagar commissionerate said.

According to the officer, they had received specific information that at least three call centres were operating from separate houses in Baguiati.

“The persons were posing as representatives of mobile network service providers. They would call people and say their terrace had been chosen to set up a mobile tower, for which they would get Rs 20 lakh and a monthly rent of Rs 15,000 to Rs 25,000,” said the officer.

Those who agreed to let out their roofs or land would then be asked to pay a processing fee ranging from Rs 10,000 to Rs 25,000, the officer said.

“Once the victims paid the initial amount, they would be asked to deposit another Rs 50,000 as licence fee,” the officer said.

As soon as the payment was made, the callers would snap all ties with the owners or occupants of the premises, the officer said.

“We first raided a call centre in Prafulla Kanan AB Block in Baguiati. There we found two men and a woman placing calls. All three were arrested,” said the officer.

Two more houses in the area were raided, from where nine men were arrested.