Detective Sergeant Flynn said US authorities were waiting to receive a green light from the Queensland Department of Public Prosecutions to take Watson into custody in Helena, ahead of a potential extradition battle in the US courts. "They are doing everything they need to do as far as dotting the i's and crossing the t's so to speak," Flynn said.

"Basically as soon as the paperwork gets drawn up and sent over through Interpol, then we will work with the (US) Department of Justice to handle it on our end." Watson and Tina married in Birmingham, Alabama, on October 11, 2003 and travelled to Australia for their honeymoon. Tina died during a diving expedition with her husband off the Queensland coast 11 days after the wedding.

One theory presented at the coronial inquest was that Watson turned off his wife's air supply, restrained her underwater, and then turned it back on when she was dead or nearly dead. The case has received plenty of media attention in the US, including an investigation by NBC TV current affairs program Dateline.

It took another sensational turn when Detective Sergeant Flynn videotaped Watson using a bolt-cutter to remove flowers laid at Tina's grave by her mourning parents. The detective staked out the Alabama cemetery for two days with a camera to discover who was tossing the flowers away. "Just when you think it's not going to get more bizarre or take a turn for the more macabre, it tends to," Flynn said.

"Her dad said 'ever since we buried her we had flowers turn up missing. What can we do?'. "Never in all my years have I heard of flowers turning up missing in a cemetery.

"So we decided to set up some surveillance on the grave to see who it was and lo and behold, there he (Watson) came." AAP