"The case was with the Andhra Pradesh Police and now the Ministry of Home Affairs has transferred the case to NIA," said a senior Indian Police Service officer.
On December 20, the Indian intelligence agencies busted an espionage racket linked to Pakistan with the arrest of seven Indian Navy personnel and a hawala operator.
The arrest of the seven naval officials from Mumbai, Karvar and Vishakapatnam for leaking sensitive information about the movements of warships and submarines to Pakistani agents had exposed lapses in the security apparatus placed around critical assets in India.
"Three sailors were arrested from Visakhapatnam, two from Karwar and two from Mumbai," said intelligence agencies which busted the espionage racket being run by Pakistan.
The agencies had stated that both Eastern and Western naval command centres, responsible for the security of the maritime borders with China and Pakistan, were exposed to these Pakistani agents.
"Some more suspects are being questioned," the agencies said.
The agencies pointed that Vishakapatnam, the headquarters of the Eastern Command of the Indian Navy and also the base of the nuclear submarine Arihant, was exposed to the espionage racket. It also stated that the Eastern Command keeps vigil upon the suspicious Chinese ship movements in the Indian waters.
The western naval command is located in Mumbai from where all nefarious activities carried out by Pakistan was also exposed and so was Karvar, the naval centre which has force's lone aircraft carrier Vikramaditya.
The Indian Navy, however, maintained that all of their critical assets were intact and there was no breach.
Earler, the navy said: "In a joint operation with the Naval Intelligence and Central Intelligence Agencies, Andhra Pradesh Police arrested some junior navy personnel. The case is under investigation by the Andhra Pradesh Police.
The Andhra Pradesh Police intelligence wing had also said that they have busted the racket under an operation named 'Dolphin's Nose' in association with the central intelligence agencies and Naval Intelligence.
The accused were produced before a court in Vijayawada on December 20. They were remanded to the judicial custody till January 3.
The police had said that all the arrested officials were in touch with Pakistani women who had befriended them on Facebook.
It is alleged that officials were paid through a hawala operator for providing information. The chats between these sailors, who were being used by Pakistanis, were sexually explicit.
Sources said the women, who honey trapped the navy personnel posing as their friends on Facebook, were set up by the Pakistani intelligence operatives. The sailors were later blackmailed and forced to give information.
"We are further probing the matter and more people could be arrested," said agencies.
( With inputs from IANS )