A public investigation into the deaths of Ben Smart and Olivia Hope claims Olivia was seen five days after police say she was murdered by Scott Watson.
Watson is serving 19 years for killing the pair after a 1997 New Year's Eve party in the Marlborough Sounds.
MORE:Â Ian Wishart claims to have solved case
The Maritime Research Group claims to name the mystery ketch linked to their disappearance in the Marlborough Sounds in 1998.
It's produced a photo it said is of Olivia Hope - taken five days after Watson's said to have killed her.
New Zealand Herald reporter David Fisher said the group's most startling claim is that Olivia Hope was alive on January 5th.
"The evidence that's put forward to support that claim is a photograph of a woman who appears to have blonde hair on the back of a runabout - the authors of the report would have it that that's Olivia Hope."
David Fisher said the photograph is distant and grainy, and the original negative is missing.
 Fisher said the report takes us back to where we were 17 years ago when Watson was convicted.
He said then - and now - there's suspicion about the police investigation, and a lack of faith in the prosecution against Watson.
David Fisher said police are aware of the contents of the report and the authors' theories - but believe no one other than Scott Watson is responsible.
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