PETALING JAYA (THE STAR/ASIA NEWS NETWORK) - An oil tanker's captain, chief officer and chief engineer may have been in cahoots with pirates who pulled off a daring theft on board the vessel Naniwa Maru 1.

The three - all Indonesians - were missing when the pirates fled after stealing three million litres of diesel from the tanker. Their passports, personal belongings and clothing were also missing from their rooms.

The three have been identified as captain Farizal, chief engineer Mohamad Alfan and chief officer Ariyandri Alhafsyah.

No ransom demand has been made for them either.

The Indonesian pirates tied up 18 crew members as they siphoned diesel from the Singapore-owned vessel at about 1am on Tuesday.

Federal Marine Police deputy commander Asst Comm Abdul Rahim Abdullah said it was very suspicious that three of the ship's key officers had gone missing with the eight pirates.

"The ship was en route to Myanmar from a Singaporean port when it was hijacked by men armed with parangs and a pistol.

"The crew, comprising 10 Indonesians, seven Thais and an Indian national, were overpowered and robbed before being locked in a room," he told reporters yesterday.

The stolen loot comprised handphones and money of various currencies amounting to US$17,000 (S$21,350).

According to ACP Abdul Rahim, two ships had berthed near the Naniwa Maru I, which was carrying 5.3 million litres of diesel, as the pirates ransacked the oil tanker.

"The pirates then siphoned 3.2 million litres of diesel out of the Naniwa Maru I into the two vessels.

"The estimated loss from the siphoned fuel was RM8 million (S$3.1 million)," he said.

ACP Abdul Rahim said the Singaporean shipping agency which owned the Naniwa Maru I was informed by the remaining crew members of the incident at 10am on Tuesday.

The crewmen, too, have come under suspicion as they waited too long to lodge a report.

"Even more suspicious is that no distress signal was activated the entire time," he said, adding that it would take at least eight hours for the two ships to siphon the diesel into their vessels.