Speaking to reporters here, Vasan said several questions have to be answered and the investigation will bring out the truth.
Meanwhile, the Q branch of the Tamil Nadu police began its investigation with the case being transferred to it from the marine police.
The Q branch monitors activities of banned organisations and people associated with such groups.
Speaking to IANS over phone from Tuticorin, a marine police official said the division's role will end with Q branch taking over the case.
Flying West African country Sierra Leone's flag, Seaman Guard Ohio, owned by US company AdvanFort was in Indian waters Friday night around 15 nautical miles from Tuticorin port.
The Indian Coast Guard escorted the ship with 35 members (10 crew and 25 security guards) to Tuticorin port, around 600 km from here.
Officials from different security departments are questioning members of the ship as automatic rifles, bullets and other arms were found on board the vessel.
The marine police Monday registered a first information report (FIR) against the ship crew and other members.
According to the Coast Guard, the vessel was manned by a 10-member crew, of which eight are Indians and two Ukrainians.
The vessel also had 25 security guards - six British, 14 Estonians, one Ukrainian and four Indians.
According to a website that tracks marine traffic, the last known port of call for the ship was Sharjah.
However, no clear picture is emerging as to why the armed ship entered the Indian waters and bought fuel illegally.
AdvanFort claims the ship entered the Indian waters to escape the fury of cyclone Phailin.
Curiously, the cyclone hit Odisha and Andhra Pradesh far off from Tuticorin where the ship was detected. It is also not known what the ship was doing in the Bay of Bengal instead of the Indian Ocean.
--IANS (Posted on 16-10-2013)