The trio -- contract labourer of the Garden Reach Shipbuilders and Engineers Ltd Irshad Ansari (51), his son Asfaq Ansari (23) and relative Mohammed Jahangir -- were arrested this afternoon from the Dr Sudhir Bose Road in the Iqbalpur police station area in the southern part of the city, a senior STF officer said.
Besides several documents revealing their links to the ISI, the STF also recovered Fake Indian Currency Note of a face value Rs two lakh from Irshad and Rs 1.5 lakh from his son Asfaq and Jahangir respectively, he said.
The police claimed that both Irshad and Jahangir were working for the Pakistani spy agency for more than 10 years and that they were passing on information from the country.
The role of Asfaq, who is a second year BA student of a south Kolkata college, is yet to be ascertained, he said.
"They had been visiting Pakistan for several years and there they were trained by the ISI for this specific service. We are investigating further into their roles," he said.
Asked whether these trio had any connection with a Pakistani agent arrested by the Uttar Pradesh STF in Meerut, the officer said: "We cannot neglect that also. We will get in touch with the UP STF."
The GRSE is one of the country's leading shipyards which mainly builds and repairs commercial and naval vessels.
The Kolkata Police STF had arrested a brother duo -- Akhtar and Jaffar Khan -- as suspected ISI agents from Collin street a few weeks back.