Thiruvananthapuram: Further probe into the high-profile gold smuggling case with overseas links will prove to be crucial to senior IAS official M Sivasankar, who is under a cloud after his close ties to the top accused, including Swapna Suresh, were revealed.

Probe agencies have not taken at face value Sivasankar's claim that he only had friendly ties with the accused in the gold smuggling case.

Three of them Swapna, P S Sarith Kumar and Sandeep Nair, have been arrested in the case.

The National Investigation Agency (NIA) plans to collect maximum evidence by interrogating Swapna and Sarith. The NIA probe is yet to focus on Sivasankar, former Principal Secretary to the Kerala Chief Minister, according to sources. Before that, the procedures of the Customs have to be completed.

Sandeep, the keyman

The NIA sleuths suspect that Sandeep is the lynchpin of the racket that utilised diplomatic baggage to smuggle gold.

Sandeep allegedly has several years of association with the various smuggling gangs in Kerala, including the notorious Koduvally gang.

Sivasankar had said in his statements that he knew Sandeep just as Swapna's friend. He will be further cornered if the probe officers find evidence such as photos or phone calls linking them.

Sivasankar reportedly had been with the accused at hotels and flats, and also arranged a flat for them. Though these are crucial in the probe against Sivasankar, the NIA is looking for more solid evidence.

Travel, call records under scanner

The probe team is checking the travel and phone call records of Sivasankar and the accused. It is also checking if they met after the gold sent from Dubai reached Kerala where it was seized by the Customs at the Trivandrum International Airport early this month.

The sleuths are also ascertaining the identity of visitors to Sivasankar's flat in the Kerala capital as well as the travel records of the vehicles used by the bureaucrat.

Sandeep, Swapna and Sarith had procured new SIM cards just for this operation. Also, the phone calls made by Swapna before fleeing from Thiruvananthapuram are also under the scanner. The last mobile tower location of Swapna's number was at Poojappura.

Swapna and Sandeep were on the run after their names cropped up in the case. The duo were nabbed from Bengaluru by the NIA on Saturday.

The case pertains to the Customs seizure of 30kg gold from a diplomatic baggage addressed to the UAE Consulate in Thiruvananthapuram on July 5. The Union Home Ministry had directed the NIA to take over the probe last week.