The family of a pensioner murdered by her porn-addicted son-in-law in a horrific sex attack today spoke of their “devastation”.

Mohammud Yusuf, 32, is facing life in jail after inflicting “the most agonising death imaginable” on Amoe Stevens, 64, leaving her to bleed to death in a chair in her own home.

Yusuf denied responsibility for the injuries but was convicted of murder by jury at the Old Bailey yesterday.

Judge Nicholas Browne QC, who was visibly shocked by the case, said Mr Yusuf had shown “no remorse”.

He added: “This lady suffered the most agonising death imaginable. I have never come across such a factual background of a case like this.”

As the jury announced its verdict, Yusuf’s wife, Margaret Stevens, wept and had to be comforted by the court matron.

A statement released by her family today said: “We are devastated by the loss of our beloved Amoe. We can’t imagine how we will ever come to terms with our loss.”

Police were called to the victim’s address in Neasden, north west London, after a carer found Mrs Stevens slumped in her chair at 8pm on 18 October last year. She was rushed to hospital but later died from her injuries.

The court heard how Yusuf’s wife had left him at the home they shared with her frail mother in Cairnfield Avenue. But within moments he had locked himself in her bedroom to assault her.

Examination of Yusuf’s phone later revealed searches for pornographic videos showing violent rape and incest.

Prosecutor David Jeremy QC told the jury there was a link between Yusuf’s interest “in pain and degradation of women and what happened to Mrs Stevens”.

Both Yusuf’s sons gave evidence to the jury about hearing their grandmother’s cries during the attack.

The court heard both are suffering emotional problems as a result of the case.

Mr Jeremy said: “They are struck most of all by the complete lack of remorse that the defendant has shown. He has made the experience even more agonising by refusing to face up to what he did.”

DCI Noel McHugh said: “Mrs Stevens suffered ill health and Yusuf should have offered her care and protection. Instead he chose to use her vulnerabilities to his own sexual benefit and violated her in the most despicable way possible.

“We believe Yusuf had assaulted Mrs Stevens on multiple occasions but due to her disabilities she was never able to communicate with her family and expose his sickening actions.”

Yusuf will be sentenced on Friday.