The daughter of coast path murder victims Peter and Gwenda Dixon has told how she had visited Pembrokeshire every summer with her parents before the fateful holiday in 1989.

But Julie Dixon - now Julie Pratley - had not been with them that day because she had been getting older, and went to Cyprus with a friend instead.

Her brother, Tim Dixon, had visited his parents at Howelston Caravan park near Little Haven but left two days before they are thought to have been killed.

The prosecution claims that John William Cooper confronted Mr and Mrs Dixon on the coastpath near Little Haven and blasted them to death with a shotgun.

The alarm was raised after Mrs Pratley returned to the UK the day after her parents were due to have been home.

The court has also heard that handwriting on the side of a shotgun cartridge box found at Cooper's home could have been that of Scoveston Manor murder victim Helen Thomas.

Forensic scientist and handwriting expert Dr Hilary Brenda Pritchard said there was "moderate" scientific support for the conclusion.

The prosecution at Swansea crown court allege that Cooper, aged 66, stole the box after breaking into Scoveston Manor in 1985.

Before he left, said prosecuting counsel Gerard Elias, he had shot dead millionaire farmer Richard Thomas, 58, and his sister Helen, aged 56.

The box of Baikal shotgun cartridges was found by police buried under a duck run at Cooper's then home in St Mary's Park, Jordanston, as they investigated a series of burglaries carried out during the 1980s and 1990s. Cooper was later convicted and jailed for 16 years.

Some of the exhibits found in that investigation were retained and, between 2007 and 2009, subjected to new DNA techniques, which led to the murder charges.

Dr Pritchard said she had been given cheques written by Miss Thomas, a calendar she had made a note on and other documents bearing her handwriting.

She compared those with a word written on the side of the cartridge box, which she believed read "Maximum 5."

"There were similarities and no significant differences," she said.

Dr Pritchard said she had started her career at London's Metropolitan police.

Mark Evans QC, representing Cooper, told the jury he would be calling as a witness for the defence "her then boss and the man who taught her."

Cooper denies all the charges against him and the trial continues.