An American man convicted in the death of his wife during a honeymoon scuba dive was released from an Australian jail Thursday and taken into immigration custody, where he will remain until officials are convinced he won't face the death penalty if sent home.

Australia is a staunch opponent of the death penalty and is seeking assurances that Gabe Watson won't face capital charges if he is returned to Alabama, a pro-death penalty state that wants to try him again over his wife's death.

Watson, dubbed the "Honeymoon Killer" by the Australian media, pleaded guilty to manslaughter in the death of his wife of 11 days, 26-year-old Tina Watson, during a 2003 scuba diving trip on the Great Barrier Reef.

Officials in Queensland state initially charged him with murder, arguing he killed Tina by turning off her air supply and holding her underwater. Watson pleaded guilty to a lesser charge last year in an Australian court and was sentenced to 18 months — a punishment Tina Watson's family and Alabama authorities slammed as far too lenient.

Queensland Coroner David Glasgow said a possible motive for the killing was Tina Watson's modest life insurance policy.

A spokesman for the Department of Immigration and Citizenship said Watson will be held at the detention center until Australia is assured he will not face the death penalty back home. He spoke on customary condition of anonymity.

Alabama Attorney General Troy King has said he believes Watson devised a plot in Alabama to kill his wife on their honeymoon, which would give the state jurisdiction to charge him. King has argued there are no international standards on double jeopardy that prevent the U.S. state from trying Watson again over the death.

Last month, a grand jury met in Birmingham, Alabama, to decide whether to indict Watson in his wife's death. It's unclear what the outcome of that session was because prosecutors haven't said and indictments in Alabama are not considered public record until a suspect has been arrested.

Under Australia's Extradition Act, a person can't be deported to face prosecution on a capital charge, unless there is an assurance the death penalty will not be imposed.

In September, Queensland Attorney General Cameron Dick said King had promised him Watson would not face a death sentence.

But on Wednesday, Immigration Minister Chris Bowen said Australia was still in discussions with the U.S. government over what charges Watson might face and whether any of those could carry the death penalty.

"If it is reasonably foreseeable that there is a real risk that an individual will face the death penalty if returned, Australia will generally require assurances from the receiving country that the death penalty will not be carried out," Bowen said.

Watson's Australian lawyer, Adrian Braithwaite, said he has asked Bowen to grant Watson a temporary visa so he can be released from the detention center while negotiations continue. Braithwaite said he's been told the process could take weeks or months.

Watson's case is also not an extradition — it's a deportation case, so how it applies under the Extradition Act is unclear.

Don Rothwell, a specialist in international law at The Australian National University, said Australia appears to be taking a very careful approach to ensure it's fulfilling its international obligations on human rights.

"Watson is in a sort of twilight zone because he's not an Australian, Australia really doesn't have any interest in him any longer, he's an American citizen, his residency is in the United States," Rothwell said.

In 2008, nearly five years after Tina drowned, the Queensland coroner found there was sufficient evidence to charge Watson with her death. A few months later, prosecutors officially charged him with murder.

In 2009, Watson — who had remarried — traveled to Australia to face trial. He later pleaded guilty to the reduced charge of manslaughter and began serving his sentence in a Queensland jail.

Braithwaite said Watson had been eager to return to the U.S., particularly because he wants to see his new wife. Now, however, Watson is having second thoughts.

"He doesn't want to go back if there's a risk that there's a needle stuck up his arm," Braithwaite said.