The handling of forensic evidence presented in Scott Watson's 1999 murder trial is under the spotlight on day two of his hearing at the Court of Appeal.
Watson, who has been in prison for nearly 25 years, is appealing his convictions for killing Ben Smart and Olivia Hope in the Marlborough Sounds after a 1997 New Year's Eve party.
The Crown successfully argued at trial that two long blonde hairs found on a blanket in Watson's boat were linked to Olivia.
They were handled by an ESR scientist Sue Vintiner, whose procedures have been criticised as deficient in the Court of Appeal.
Forensic scientist Sean Doyle reviewed her work and told the court she deviated from standard methods, opting to follow personal preference, raising the risk of contamination.
"Because she's using her own personal judgement, I would expect a detailed record to be made, and certainly recording what she actually did in terms of, well, I cut the bags open, I put the tweezers in and I pulled the hair out."
The Crown successfully argued at trial that two long blonde hairs found on a blanket in Watson's boat were linked to Olivia. (Source: 1News)
“And I say that surprisingly to me doesn't appear, or I can't find it in the case files.”
"And I think that's a very significant piece of information," Doyle told the court.
His evaluation of Vintiner's work was commissioned by Brian McDonald, a Watson supporter, as part of an earlier appeal.
Doyle said Vintiner didn't change her white lab coat between examining the reference hairs, taken from Olivia's bedroom, and the ones in question found on the blanket.
"Today you'd have full barrier clothing, you'd be suited, booted, hat-ed, masked, and you'd change your barrier clothing between, certainly between the examination of question and reference materials," said Doyle.
One of New Zealand’s most high-profile and controversial murder cases is back before the courts this week, as Scott Watson challenges his convictions for the murders of Ben Smart and Olivia Hope in the Marlborough Sounds in 1998. (Source: 1News)
His report suggested a system not fully under control and he called Vintiner a part-time hair examiner.
Under cross-examination Crown lawyer Robin McCoubrey suggested he was trying to undermine Vintiner.
"You're trying to portray a rather chaotic laboratory which was substandard and a part-time scientist who wasn't very experienced and needed people to help her out with her hair examination and standing back from it, that's not a fair evaluation of what happened here, is it?"
"Well, I was a forensic scientist in 1998 and I can assure you the world was a very different place in terms of forensic science then," Doyle replied.
The possibility of contamination was raised at trial. McCoubrey reminded Doyle of the direction the trial judge gave the jury.
"It's not trial by scientist, it's trial by jury, and that it was for the jury to consider the scientific evidence and such concessions," said McCoubrey.
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