Jifsal CV, Aboobacker P, Muhammed A Shameem, and Abdul Hameed PM were arrested on Monday on charges of conspiracy and financing the smuggling of gold through import cargo addressed to the UAE consulate at Thiruvananthapuram. They also allegedly received such smuggled gold and proceeds from the crime.

The agency said that it conducted searches at the houses of these four in Malappuram and Kozhikode districts as well as at Malabar Jewellery owned by Aboobacker, Ameen Gold in Malappuram owned by Abdul Hameed, and Ambi Jewellery in Kozhikode owned by Shamsudheen.

"Several digital devices and incriminating documents were seized," the official said.

So far, the NIA has zeroed in on 25 accused, of which 20 have been arrested.

The gold smuggling case was unearthed when Sarith, a former employee of the UAE Consulate in Thiruvananthapuram, was arrested by the Customs on July 5 when he was facilitating smuggling of 30 kg gold in diplomatic baggage to the state capital from Dubai.

Things turned murkier when the name of Swapna Suresh, a former employee of the Consulate and later employed with the IT Department, surfaced. Later, her links with now-suspended IAS officer M Sivasankar, then posted as Principal secretary to Kerala CM Pinarayi Vijayan and also the IT Secretary, came to light.