Expert says gouges made by fingernails

By Eugene Bingham and Alison Horwood

Fingernails clipped to the end of a finger were long enough to gouge marks on the hatch cover on Scott Watson's boat, a forensic scientist said yesterday.

Peter Wilson, from the Institute of Environmental Science and Research, said he had concluded that the 176 scratches on the hatch cover's foam lining were caused by fingernails.

The jury has already heard how Olivia's love of piano meant she kept her nails closely cropped. Her father, Gerald Hope, was questioned on whether they were too "stubby" to mark the hatch.

Mr Wilson told the Watson double-murder trial that he carried out experiments with various fingernail lengths.

"A nail in line with the end of the finger was sufficiently long to mark the hatch cover.

"A medium-length fingernail just protruding over the end of the finger left a deeper mark than a longer fingernail."

Mr Wilson said he had used a Phillips screwdriver, a flat-head screwdriver, a metal spatula, a metal ruler and his own fingernails in an attempt to duplicate the marks discovered on Watson's yacht, Blade.

The marks created by his fingernails on a weathered piece of foam similar to that on the boat had the same appearance as the scratches on the hatch cover.

"When I used a screwdriver and the end of a metal ruler, I found they left marks that were different in appearance from those on the hatch cover."

Mr Wilson said he first inspected the marks when police sent the cover to his Lower Hutt laboratory in March last year.

He noticed the marks were multi-directional and varied in size. The longest was 360mm, while the shortest was 10mm. The width varied from 2mm to 10mm.

Crown prosecutor Paul Davison, QC, asked Mr Wilson if it was possible for a child under 10 years old to have left the marks.

"I would say it would be possible for a child to make the narrower marks but unlikely to make the 10mm wide marks because the fingernail would not be wide enough."

In May this year, Mr Wilson was present when a scientist employed by the defence counsel inspected the hatch cover reattached to Blade.

At that time, he noticed some scratch marks could not have been made when the hatch cover was fully closed because of a 50mm overlap between the cover and the hole.

Asked by Mr Davison how high the hatch cover needed to be for such marks, Mr Wilson said: "I felt the front of the hatch had to be lifted about 60mm and then you could get your fingernails into the back."

Under cross-examination, Mr Wilson was challenged about how he had come to his conclusion that fingernails had caused the marks.

He agreed with defence counsel Bruce Davidson that he had been sent a list of all the items on Blade. After scanning through the list, he decided nothing on it could have caused the marks, though he did not ask for anything to be sent to him for testing.

Mr Davidson: Keys?

Mr Wilson: I felt they were greater than the width of the ruler and also a flat screwdriver, so I felt you could rule it out on that basis. One would end up trying anything in creation, anything that may have any shape, so one makes a decision as to what type of object has made these marks.

Mr Davidson: But here was a list of items provided to you by the police that you were asked to consider. So did you consider, for example, the keys?

Mr Wilson: I considered the items that were listed ... nail clippers, anything that had any rounded shape but was narrow enough to dig into the foam.

Mr Davidson: Plastic pegs?

Mr Wilson: One cannot be absolutely sure of anything in this world unless one tries, and I did not try the round shape of a peg but made an assumption about its thickness.

Mr Davidson: Scissors, protractor, corkscrew?

Mr Wilson: I felt they were unlikely to make the marks.

The court also heard how Watson consented to give police a blood sample in Picton on January 14 last year.