Braun, along with an expert on oceans, told DailyMail.com her body would almost certainly have washed up on the shore by now if she drowned.
An accidental drowning seems unlikely.
The water wasn't rough that night, no high tide, and no rip currents, so she likely wasn't simply swept away,' Braun said.
'Keeping focus on her likely being alive increases the chances of finding her.'
Stephen Leatherman, a professor of Earth and Environment at Florida International University, also thought eight days was too long for her body to be at sea.
'If she drowned, her body should have already surfaced in the warm Caribbean waters,' he said.
'I have served as an expert witness for 30 years, so I have been involved in many cases where someone drowned in a rip current, but the body was always recovered.
'I think that there must be another explanation for her disappearance.'
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footage showed the Konanki vomiting at 4.05am before walking back to the bar. Riibe remained in the background vomiting while two men stood near him.