Police videos have revealed how the daughter and grandson of an 84-year-old woman repeatedly denied her murder.
Penelope John and Barry Rogers were given life sentences in February, with a minimum of 11 years.
They both pleaded not guilty to murder at Swansea and under cross-examination denied being everything.
Grandson Barry Rogers was arrested after an ex-partner told police he had confessed to killing frail Betty Guy at her home in Johnston near Haverfordwest in Pembrokeshire.
Police arrested his mother, Penelope John, when they realised that she had lied about Betty’s medical condition in a call to emergency services the night Betty died.
Now police tapes, to be broadcast on ITV Wales’ Crime Files at 8pm on Monday night, show how those lies continued as the mother and son were interviewed by police officers.
Barry Rogers, a 33-year-old ex-soldier told how he drove, “pretty fast”, from his home in Frome, Somerset to his grandmother’s home in Pembrokeshire. But he insisted: “By the time I got there, my Nan had already died.
“My Nan died of old age, just old age”, he told officers. “She was 84. She wasn’t a spring chicken anymore.”
His account was challenged by an officer during an interview.
“Is it a case that you saw your Nan was in so much pain that you took it upon yourself to end her life, to end her misery?”, she asked, but Rogers continued to deny any involvement.
In another police interview in the programme, Penelope John is seen insisting her mum died on her own. But covert police recordings revealed her son confessing.
Penelope John was challenged about the admission but said: “I didn’t hear that. I don’t know but my Mum died by herself and I was in the bedroom”.
Tearfully, she insisted: “She was everything to me. Everything. And all this is horrible.”
Both went on to appeal their sentence but lost the appeals.
- Crime Files will be broadcast on ITV Wales at 8pm on Monday 17th September and will then be available at itv.com/walesprogrammes.