"Tragic Accident" or Murder?

A murder mystery is unfolding in the British Virgin Islands. The owner of a Rhode Island scuba shop is there on trial for allegedly drowning his wife.

But if it weren't for the victim's parents, the case might not have surfaced at all. "Early Show" national correspondent Hattie Kauffman reported Shelley Tyre died in the waters off the British Virgin Islands, but no one knows how it happened.

Shelley's husband David Swain, who is now on trial for her murder told CBS News it was a "tragic accident."

Three years after a Rhode Island civil suit found him responsible for his wife's death, Swain is on trial for murder in the Caribbean. Swain and his wife were both highly-experienced divers when they went scuba diving in 1999.

Swain is accused of ripping off his wife's mask and cutting off her air supply. But he argues, "From the time I left her to the next time I saw her, any number of things could have happened."

Jennifer Swain-Bloom, Swain's daughter, said, "He loved her so much. And he loved diving so much. To lose her to something he loved, no one deserves that."

At first, Kauffman reported, authorities in the British territory found no evidence of foul play. But the victim's parents felt otherwise, and filed a civil suit, ultimately winning damages totaling $4.8 million.

However, Richard Tyre, Shelley's father, said money has nothing to do with their case. "We just want Shelley," he said.

Shelley's estate was worth $570,000, but that money was quickly spent by her husband -- a point brought up by the attorney for Shelley's parents.

J.Renn Olenn, the victim's parents' attorney, said Swain spending Shelley's money is important.

Olenn said, "It shows motive."

Prosecutors in the British Virgin Islands also say Swain wanted his wife out of the way to pursue a romance with another woman.

But Swain-Bloom said she believes her father is "absolutely innocent."

"He did nothing wrong that day," she told CBS News. "He was there enjoying the dive. And it went horribly wrong."

David Swain said, "To say what happened (to my wife), I can't answer that."

If convicted, David Swain faces life in prison.