Soon after the incident, Navy Chief Admiral D K Joshi had said that the sabotage angle in the incident cannot be ruled out.
"We cannot rule out sabotage... But indications at this point do not support the (sabotage) theory," he had said.
The submarine sunk with its crew of 18 personnel including 15 sailors after two major explosions on it were seen from a distance.
The Navy sources said the blast may have occurred in the torpedoes in the front portion of the submarine around which the accommodation of the crew are also located.
The sources said attempts would be made to bring up the warship up from the seabed which will help in the investigations into the incident.
They said the possibility of using the submarine again seems to be very low as the explosion has caused great damage to the structure of the vessel where steel has melted and fused with other structures.