Coming a week after Pakistan Army commandoes killed five Indian Army soldiers in Jammu’s Poonch sector on August 6, 2013, the submarine incident made the Indian Navy and Intelligence agencies examine the sabotage angle with a needle of suspicion on Pakistan-based groups.
Not only did the Intelligence agencies scour technical inputs and communication intercepts within the country and across the western border, the antecedents and past records of all those involved with Sindhurakshak were verified by the Navy intelligence to rule out internal sabotage.
While it appears that Islamabad itself was taken by surprise over the sinking, the possibility of any commando raid at the Mumbai harbour was ruled out as the Navy was on high alert after the Poonch killing and massive steel nets were protecting the ingress route into the anchorage area. In fact, two sister Kilo-class submarines were sent on sea patrol within two hours of the incident to neutralise any hostile intentions in the vicinity.
Movements, speeches and communication among terrorist groups across the border were kept under watch to unearth any involvement.
While the board of inquiry set up to investigate the submarine tragedy will only be able to give its report after the boat has been salvaged, there are indicators pointing to explosion in the torpedo chamber or on-board compressed oxygen cylinders.