The officer has been directed to appear before the investigation agency again on Tuesday, his lawyer told reporters here.
This is the second time in the past one week the NIA grilled the officer, removed as Principal Secretary to Chief Minister Pinarayi Vijayan and the state IT Secretary after allegations of his link with a key woman accused in the case surfaced. The Customs department had also questioned him earlier.
Sivasankar left the NIA office here at 7 pm after the day-long questioning by the investigation team. He arrived there around 9.20 am in response to summons. The officer's lawyer said his client will cooperate with the investigation.
Earlier on July 23, Sivasankar was questioned for five hours by the NIA team at the Peroorkada police club in Thiruvananthapuram. The senior bureaucrat, suspended based on the report by a high-level committee that went into allegations against him, had been questioned by Customs, which is also probing the case, for nearly nine hours, lasting till the early hours of July 15.
Action was taken against Sivasankar after allegations surfaced that he had links with Swapna Suresh, the key accused in the case related to the attempt to smuggle gold through diplomatic baggage using the name of a person in the United Arab Emirates (UAE) consulate in Thiruvananthapuram. The Customs seized the gold, weighing over 30 kg and valued at around Rs 15 crore on July 5.
The NIA, which has been entrusted with the probe into the case, has booked Suresh and three others -- Sarith, Sandeep Nair and Faizal Fareed-- under the Unlawful Activities (Prevention) Act. Suresh and Sarith were former employees of the UAE consulate and allegedly used their past connection to smuggle gold using the diplomatic channel.