Image copyright Gwent Police Image caption The court heard traces of heroin and cocaine were found in Owens' blood after the murder

A man who murdered his mother with a chainsaw has been found dead in prison.

Robert Owens killed Iris Owens, 75, in May 2016, as she was putting out washing at their home in Ystrad Mynach, Caerphilly county.

He was jailed later that year at Cardiff Crown Court for a minimum of 12 years and six months.

Owens, 50, died in Long Lartin Prison in Worcestershire, on 14 July and the Prisons and Probation Ombudsman is investigating.

He admitted his mother's murder and Cardiff Crown Court was told at the time Mrs Owens, a retired history lecturer, sustained five separate contacts with the chainsaw and was also strangled and kicked.

Owens was cutting some firewood when he claimed his mother "went mad" and the pair argued.

She pushed him, he said, and he pushed her back before attacking her with the chainsaw.

When asked about his medical history, Owens said he was a heroin addict and had last taken the drug at midnight the night before the murder. Tests revealed morphine, heroin and cocaine in his system.

Image copyright Gwent Police Image caption Iris Owens was a published author and volunteered for several charities

Judge Mrs Justice Nicola Davies told Owens it was a "tragic and senseless murder of a good mother by her son".

She said it would have been a "terrifying ordeal" for Mrs Owens, adding: "I accept that you are genuinely remorseful for the brutal acts you inflicted upon your mother."

Mrs Owens was described as a "very well-educated" woman who had achieved a first-class degree in English when she was 64.

She was a published author, volunteered for several charities and was a bilingual tour guide at Llancaiach Fawr Manor.

She and Owens were "very close" and he moved into her home following a divorce in 2006.