IN the days after an experienced cook disappeared overboard from a giant coal carrying ship off the Queensland coastline, police considered it a potential murder investigation.
They were not the only ones.
A coronial inquest into how two Filipino sailors died aboard the Sage Sagittarius or "death ship" returned on Monday.
The suspected death of chief cook Cesar Llanto on August 30 rang alarm bells for the Australian Federal Police and the ship's owners.
The inquest heard an executive with owners NYK Line flagged to a colleague by email that "one crew of the vessel has been missed" from the Sagittarius, which has previously visited ports in Gladstone and Abbot Point.
NYK Australia's Shigehiko Ochiai told fellow executive Jason Glynn to take action because he feared there could be a threat on board.
"NYK Tokyo has organised crisis management to fix this incident because there is a few possibility of murder," Mr Ochiai wrote.
When questioned about this email, Mr Glynn told the inquest he was not overly concerned because he thought it was a translation error.
The following day he helped organise security guards to accompany two NYK staff who were flying in to board the ship off Brisbane.
They were not the only ones concerned about safety.
AFP Detective Sergeant Nuckhley Succar was the first case officer for the investigation.
He told the inquest he did not consider Mr Llanto's death to be the result of suicide or workplace accident.
His view was that the death was "highly suspicious so the investigation commenced into the alleged murder".
This evidence shows for the first time that Mr Llanto's death was immediately considered a potential homicide.
FOLLOW OUR MAJOR INVESTIGATION: ABOARD THE DEATH SHIP
The AFP boarded the ship in Port Kembla on September 7, a week after Mr Llanto disappeared and three days after NYK staff joined the crew.
A deal struck between the AFP and NYK Line meant investigators had a single day to interview the dozens of crew members on board.
This was done to avoid the huge costs associated with delaying the vessel.
Det Sgt Succar said it meant interviewing from 6am to 11pm, and often being "hurried up" mid-interview.
After meeting their deadline, the ship travelled to nearby Newcastle where chief engineer Hector Collado would suffer a blow to his skull before falling to his death on September 14.
The inquest resumes this morning.