Defence queries how samples were found

By Eugene Bingham and Alison Horwood

Lawyers for Scott Watson have raised the possibility that scientists inadvertently mixed hairs found on the bedding of his yacht with strands taken from Olivia Hope's bedroom.

Forensic biologist Susan Vintiner said testing of a single blond hair found on a tiger-motif blanket on Blade "very strongly supported" the conclusion it was Olivia's, but later agreed with defence counsel Bruce Davidson that contamination of the samples could not be ruled out.

The scientist faced two hours of cross-examination over her handling of the samples, including questions about an unexplained slit in the plastic bag containing reference hairs taken from the Hope family home.

Susan Vintiner said that on January 22 she conducted an initial examination of the 391 hairs and removed 11. It was not until her second trawl through the strands that she discovered the two blond hairs that analysis would later reveal were likely to belong to Olivia.

She agreed with Mr Davidson that one possibility was that she overlooked the hairs during her January examination.

Mr Davidson: But another explanation is that [the hairs from the blanket] somehow or other escaped from [the bag of reference hairs] during this process of handling and mistakenly have [been] assumed to have come from the blanket. That is another explanation isn't it?

Susan Vintiner: That is one that needs to be considered.

She had told the court earlier that the purpose of the initial examination was to familiarise herself with the general appearance of the hairs from the blanket and find any strands with solid roots that would be suitable for DNA testing. The reference samples had not arrived at her laboratory in Auckland by this time.

"I certainly would have retrieved a hair if it had been any shade of blond if I had seen one, but without reference samples the principal target was just to focus on hair roots."

Susan Vintiner was also quizzed about a 1cm-long slit in the bottom right hand corner of the bag containing Olivia's reference hairs. She said she did not know how or when it happened.

Of the hairs found on the blanket, 132 were body or pubic hairs, 221 were brown head hairs, 17 were red-brown to orange-brown head hairs,16 were animal hairs and only five were blond.

DNA analysis of one of those blond hairs concluded that it was 28,000 times more likely to have come from Olivia than another fair-headed New Zealand woman, said Susan Vintiner. The second hair did not produce any DNA.

She agreed that people shed about 100 hairs a day and those strands could be transferred to other people or objects.

Mr Davidson: We have a situation where there were upwards of 1500 or possibly more people centralised at the Furneaux Lodge complex, so you would agree that the jury in this particular case would have to consider the possibility of the transference of hair from Olivia Hope to Mr Watson, and then carried by him on his clothing to his sleeping berth on his boat. The jury would have to consider that, wouldn't they?

Susan Vintiner: They should consider that.

Dr Gillian Tully, of the Forensic Science Service in England, told the court that in June last year she received at her London laboratory the two hairs uplifted from the blanket.

She analysed sections of the hair shaft for mitochondrial DNA, which she explained were gene hallmarks passed from a mother to her offspring. Susan Vintiner's tests relied upon DNA contained in the hair root and its attached cells.

Dr Tully said she was able to obtain mitochondrial DNA from the hair that Susan Vintiner was unsuccessful with. It matched the DNA profiles found in blood samples taken from Olivia Hope and her mother, Jan.