The jury in the Betty Guy murder trial has retired to consider its verdict.

Mother and son Penelope John and Barry Rogers are accused of killing Mrs Guy at her home in Johnston.

Mrs Guy was John's mother and Rogers' grandmother.

John, aged 50, of Union Terrace, St Dogmaels, and Rogers, 33, of High Street, Fishguard, deny murdering Mrs Guy during the early hours of November 7, 2011.

At first her death was put down to natural causes and her body was cremated at Narberth four days later.

Now, the prosecution claim John fed her drugs and whiskey and that Rogers "finished her off" by placing a pillow over her face.

Last week the jury heard closing addresses to the jury at Swansea crown court.

Paul Lewis QC, the barrister leading their prosecution, said both John and Rogers had dealt with police "like politicians, answering questions they wished they had been asked and not the ones that they were."

Both, he said, had changed their stories repeatedly.

"It is an unhappy case. It is hardly believable that a daughter and a grandson might kill their mother and grandmother. But that is what the evidence demonstrates," he added.

Christopher Henley QC, the barrister representing Rogers, said the "fundamental and inescapable problem" in the case was that there might not have been a crime at all.

"There is no medical evidence about the cause of death. Surely what is needed is some medical certainty that this was an unlawful death. That should be decisive to the verdicts.

"How can you be sure this old lady did not die naturally from a range and combination of significant health issues?"

Mr Henley said the prosecution could not even offer a motive for murder. Rogers inherited only a washing machine and a tumble dryer.

"The prosecution do not have to prove a motive but you might think they could suggest one," he told the jury.

John and Rogers deny murder and the trial continues.

UPDATE: 4.05pm: The jury has been sent home for the night and will continue its deliberations on Tuesday morning.