BY NEWS.com

THE inquest into the death of a woman found lying on the seabed in a honeymoon diving mystery has heard how her husband - a trained rescue diver - joked that for an extra $10 she could have had a million-dollar life insurance policy.

Just ten days into their honeymoon Gabe Watson's wife, 26-year-old former model and scuba diver Tina Watson, of Alabama, died on the Great Barrier Reef.

She had air in her tank, her equipment was working and the regulator was in her mouth.

Experts have all but ruled out the possibility of a medical problem or faulty equipment, leaving only two options: a tragic accident or foul play.

But did the honeymoon turn into murder?

State Coroner David Glasgow this week opened an inquest into the suspicious death of Christina Mae Watson on the shipwreck of the Yongala, 89km southeast of Townsville, on October 22, 2003.

The inquest was told it would be very easy to kill a novice diver underwater.

One possible scenario was that Watson deliberately turned off Tina's main air supply at a depth of 15m and five minutes into the dive.

She panicked - having only 11 previous dives - instead of unclipping her vest and turning the main valve back on herself.

Her powerfully built husband, shielded by an underwater visibility of 10-15m, might have held her in "a bearhug" as she fought to grab his secondary air supply and swim to the surface.

Starved of oxygen, she would have quickly gone into hypoxia, spasms, and in the throes of death, Watson might held her - staring into her eyes - until she died.

It was suggested he could have then turned the main air supply back on, to cover his tracks, and let her sink to the ocean floor.

Witnesses told how he appeared on the surface screaming: "I've lost my wife".

At the same time dive instructor Wade Singleton, who was on an orientation dive with three others, found her lying on the bottom "staring up at the fish".

"Then I realised there were no fish and no bubbles," Singleton told the court.

The dramatic moment when Singleton began his desperate rescue bid - with her body shown in the distance - was inadvertently captured on camera by American diver Gary Stempler.

The photo, with his wife Dawn Osana posing unwittingly in the foreground, has become a key piece of evidence before the inquest.

Watson has told 16 different versions of what happened.

He said his wife got into difficulty during strong currents and panicked.

He claimed she knocked his face mask off and the regulator out of his mouth and, unable to calm her, he headed for the surface.

What is inexplicable is why the trained rescue diver - who was taught how to rescue distressed or unconscious divers - abandoned his novice wife.

Or why it took him a "pedestrian" two minutes to return 15m to the surface.

It took rescuer Singleton a minute and a half to travel twice the distance carrying Tina's body from the sea floor in 30m of water.

One witness Dr Stanley Stutz, who was on a drop line to the wreck 15m above, said he watched Watson "bearhug" Tina before letting her go.

"The look on her face was awful, I had the belief she knew she was in danger, her eyes were wide open," his statement said.

Watson showed friends at a wake after her funeral a macabre video with him saying: "Smile at the camera, case you get eaten by shark or something."

He joked that for an extra $10 his wife could have had a million dollar life insurance policy.

But the court this week heard evidence that Watson only stood to make US$33,000 out of his wife's life insurance not US$1 million as reported in some media outlets.

He also would have only inherited a heavily mortgaged house and a motor vehicle, the court heard.

Watson, 26 at the time of the death, is suing Old Republic Insurance and Travelex for hundreds of thousands of dollars in punitive damages including the "mental anguish" of his loss.

Alabama police have named him as a suspect in the death.

Lead investigator Detective Sergeant Gary Campbell, of Townsville CIB, told the court he found "bizarre" the behaviour of Watson in trying to redeem his wife of ten days life insurance policies, his actions in having her body disinterred, the lack of a gravestone and the theft of the parents' flowers from her grave site.

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