Chennai,  Security agencies in Gabon-marine and local police of the West African nation are questioning three persons who had boarded the merchant vessel MV Tampen two days before the attack on the ship by pirates, said a senior official of Proactive Ship Management.

The ship, with 17 Indian crew, was sailing from Cameroon to the UAE when it developed some propulsion problems and was anchored just two kilometres away from Gabon's Owendo anchorage when pirates boarded the ship on Sunday morning.

While the pirates threw one of the crew overboard and shot and injured two.

"The marine and local police in Gabon are questioning three persons who had boarded the ship two days before the attack. We hope to know some information about the attackers and the missing crew today (Wednesday)," Captain Sunil Kumar, Security Officer of Proactive Ship Management, told IANS over phone from Mumbai.

The company had provided the men for manning the ship.

He said: "One garbage cleaner and two technicians had boarded the ship as per the information conveyed to us by our agent there."

According to him, the vessel was in the inner part of the port. It is suspected that those who knew the port very well might be involved.

Kumar also said the two injured sailors are doing fine and they had spoken with their family members in India.

The ship's chief officer and cook suffered bullet wounds.

Kumar said the ship was not carrying any cargo and was to go to the UAE.

According to Kumar, the two injured crew saw the ship's Second Engineer being thrown overboard. It is not known whether he was kidnapped by the pirates. He is currently missing.

The pirates had fired at the ship crew when they resisted and the Second Engineer was thrown into the sea.

Kumar said the company has informed the Indian authorities like the Directorate General of Shipping and other authorities in India and in Gabon.

Queried about the next course of action in bringing back the crew Kumar said the company can send a replacement for one of two crew who want to sign-off.

"The remaining crew are on the ship. There are armed security guards on the ship. We are paying about $700-800 per day for their services," Kumar added.

The ship is an offshore supply vessel sailing under the flag of St Kitts and Nevis.