Detention review hearings begin today for close to 500 immigrants who came to Canada last Friday aboard a rusty cargo ship.

Police have confirmed that one Tamil man died aboard the MV Sun Sea cargo ship while it was en route to Canada but not yet in Canadian waters.

According to sources, living conditions were horrific onboard the ship, with several hundred passengers sharing one toilet, and as little as one litre of fresh water allotted for each passenger, per week.

The roughly 490 Sri Lankan migrants who arrived on the ship have been held in custody since they arrived last week.

Their hearings are set to begin today in Vancouver, said Stephen Green, chair of the Canadian Bar Association.

"What will happen now is each of the migrants will have an opportunity to appear before an immigration judge and that judge will have to determine whether that person should be released into the public," Green told CTV's Canada AM on Monday.

The judge will have to determine whether each immigrant is a danger to the public, whether there is a health concern, or whether they will have to reappear at a later date, Green said.

The Canadian Border Services is doing a full investigation into each of the individuals aboard the ship to determine whether they have terrorist connections. If so, they would be kept in detention and eventually returned to Sri Lanka, Green said.

However, he urged Canadians to let the law take its course before making judgments.

"These are people making refugee claims and they fear for their lives, so they're not jumping the queue, they are in danger and they can't be sent back until they've had a full hearing to understand if there is any possibility of danger for them to return," Green said.

Burial at sea

Details are beginning to emerge about the voyage from Sri Lanka and the death of one of the passengers aboard the MV Sun Sea.

The man, a 37-year-old, died about three weeks ago, according to the RCMP. He died in international waters and was buried at sea.

Police said there was no criminal intent involved in the death, and the man simply died of sickness that was untreatable at sea.

CTV's Janet Dirks said the man died on July 28.

"He was buried at sea, he was the father of a child, he had a wife -- they remain in Sri Lanka," Dirks said.

Of the surviving passengers, Canadian authorities have said they are "pretty good" and that those taken to hospital have not been treated for any critical illnesses.

"They were maintaining that people were doing pretty well and their spirits were high," said Dirks.

"They were relieved to be in Canada, that there was even laughter on the boat, so it didn't seem like it was a terrible situation in terms of what they had discovered."

Dirks said that at least one elderly couple -- both 70-years old -- is confirmed to have travelled to Canada on board the MV Sun Sea, a detail that was previously unknown.

"We had seen photographs or images of young children, a baby, toddlers, but never older people. So now we know there is an elderly couple on board the ship and they survived," she said.

Public Safety Minister Vic Toews has warned that the ship is part of a smuggling operation that is linked to the Tamil Tigers, a terror organization that is banned in Sri Lanka.

On Sunday, Toews released a statement saying that the RCMP would answer questions relating to the death.