IT WAS lunchtime in the crew dining area on board one of the world's most luxurious ships.

The QM2 had been at sea for just a day and more than 3,000 passengers were just floors above - 24 hours into the holiday of a lifetime, cruising the fjords on a Norwegian Odyssey.

But below deck the scene was very different. Filipino ship's electrician Rodolfo Juanga had become jealous of his roommate and fellow countryman Joel Taagan, who was earning more money. As 39-year-old Mr Taagan ate his lunch of rice, Juanga began raining blows on his head with a sacrificial hammer stolen from the ship's electrical workshop - eventually killing him.

Immediately, the blood-soaked canteen that had been busy with staff eating their lunch became a crime scene. Mr Taagan was airlifted off the ship, which was about 74 miles off the coast of Holland, and 48-year-old Juanga was locked in a cabin with powers given to the Captain under the Merchant Shipping Act.

In Hampshire, detectives were preparing to take on the case - one of very few that end up with a charge of "murder on the high seas". Home Office guidelines mean that the police force at the ship's registered home port have jurisdiction for criminal investigations at sea, no matter where the ship is in the world.

Security officers from P&O were contacted, phone calls were made to establish what had happened and, within hours, a team was being prepared to fly out and meet the ship in international waters in the North Sea.

At 4am the following morning, Saturday, May 13, Det Insp Niven and his officers left the Major Crime Department (MCD) in Hulse Road, Southampton. They flew to Amsterdam, then on to Bergen in Norway, before finally reaching the liner at midday.

Det Insp Niven said: "One of the first things we had to do when we got on board was to make arrangements for the prisoner to be kept there. It was absolutely crucial because had he been taken off the ship in Norway it would have been difficult to keep him in custody while an arrest warrant was issued back in Southampton.

"He was guarded by security crew onboard the ship. More than 3,000 passengers were onboard and there were rumours that an incident had taken place and that Hampshire Police were onboard investigating but they were unaffected."

The murder of Mr Taagan, a father-of-two, had taken place below deck in the crew area.

Fighting for life and with injuries to his head from two blows, he had been taken from the ship by members of the Dutch Royal Navy in a helicopter but died in the air being transported to hospital in Holland.

"We set up an incident room. It was the first time I have ever had to run an investigation at sea but the captain and the crew were superb," said Det Insp Niven. Within hours detectives were interviewing crew and nine scenes had been identified for forensic purposes.

The investigation was being led out of a major incident room set up in the bows of the ship and 20 key witnesses had been found.

Det Insp Niven said: "Every day from 8am till 8pm, our team was below decks, completing interviews and inquiries, while the forensic examinations were conducted.

"The investigation continued with this kind of intensity until the ship docked back in Southampton following four days at sea.

"It was an unusual case. To put together a team of detectives and crime scene investigators in the time available and fly them out to meet a ship to investigate and secure a large amount of evidence - it doesn't happen very often.

"It was a rewarding feeling that the Hampshire's MCD was up to the task."

QM2 sailed back into Southampton on May 18 and a team of detectives were waiting to greet her.

Juanga was removed from the ship and taken into custody where he was interviewed over a number of days.

"Interviewing him took phenomenal time and patience," said Detective Sergeant Jim Park who led all interviews.

"From the beginning we had to prepare for all eventualities - a nocomment interview, that he may want to give us a prepared statement or that he might not answer some more difficult questions.

"Early on it became apparent that he was going to talk to us through an interpreter."

Det Sgt Park added: "He was a very cold person. There was no warmth, no emotion and no apology for what he had done.

"There was no sense of feeling. Why he did what he did was all about another member of staff receiving $100 or $200 more a month for doing the same job.

"People working on board would regularly send money back to their families. Our victim Mr Taagan, like Juanga, was supporting his wife and children as well as his extended family. In the end two families lost out."

Juanga was jailed for life for Mr Taagan's murder and faces deportation.