The trial of John Cooper, the Pembrokeshire farm labourer accused of two double murders in the 1980s, has been halted and the jury discharged.
A new jury is being sworn in and the trial is expected to restart from the beginning later today.
Mr. Cooper, of Spring Gardens, Letterston, near Haverfordwest, Pembrokeshire, denies murdering millionaire farmer Richard Thomas, 58, and his sister Helen, 56, at their home at Scoveston Park on December 22, 1985.
He also denies the murder of Oxfordshire holidaymakers Peter and Gwenda Dixon, aged 51 and 51, in June, 1989.
The trial, at Swansea crown court, was in its fifth day when Mr Justice Williams said a matter had been brought to his attention which had caused him to discharge a member of the original jury.
That had led to the whole of the jury being discharged.
Mr. Cooper also denies raping a 16-year old girl, indecently assaulting another and trying to rob money from a group of five youngsters, all on 6 March, 1996.