Italian authorities are probing why its merchant ship ignored the Italian Navy's objections and docked in Kerala leading to the arrest of two of its marines for the killing of two Indian fishermen. It is also looking at the sequence of events that has sparked an unprecedented diplomatic row between Italy and India.
A colonel is collecting evidence from military headquarters and the shipping company to ascertain if they sent Enrica Lexie into Kochi harbour in Kerala, Italian media reported.
The Italian Navy had reportedly objected to Enrica Lexie moving into Indian waters and the disembarkation of its military personnel on board, reported the Corriere della Sera, a news website.
Indian fishermen Ajesh Binki and Gelastine were allegedly mistaken for pirates and shot dead by the marines Feb 15 off the coast of Kerala.
Latorre Massimillano and Salvatore Girone were arrested by Kerala Police on murder charges.
Italy insists that the ship was in international waters when the incident took place and that the marines cannot be tried in India. New Delhi is not ready to accept either argument.
The media report said that, according to established procedure, decisions on board the ship are taken by the captain in agreement with the shipping company. But in an emergency, action is decided with the military authorities and the Italian government.
The investigation will find out if the shipping firm took the decision to leave international waters and with whom they negotiated.
Massimiliano Latorre, who was in charge of the security unit on board the oil tanker, has reconstructed the sequence of events, according to the website.
His report says that a third warning burst was aimed "into the sea across the bows of the fishing boat, which was not hit and in fact changed direction and turned back".
The report, containing photographs, denies that there could have been any casualties.
The case file has statements from the five other service personnel on board.
The media report said that there are a number of questions and the versions supplied by the Italian military personnel and the Indian authorities differ.
According to the report forwarded to Rome, the alarm was sounded at 11.30 a.m. Feb 15 February when the Enrica Lexie was "thirty-three miles off the south-west coast of India".
The position is shown by the ship's satellite link but Indian authorities contest it.
Giving the sequence of events, the security official's report said: "The radar picked up a vessel on a collision course and the marines on board prepared to react. The security unit carried out the prescribed procedures for such cases. When the vessel is 500 metres away, the first warning shots are fired. Another warning burst is fired at 300 metres and a third at 100 metres".
Latorre stated that the final warning shots are fired into the water "without striking the vessel".
However, Indian authorities claim that the fishing boat bears the marks of sixteen projectiles while four hit their target killing the two fishermen. Italian investigators and diplomats dispute this version as it would mean that all the shots were fired straight at the men.