Boy, 17, who stabbed his older sister to death pleads guilty to her murder

A 17-year-old boy who stabbed his older sister to death after telling her he wanted to practise a headlock on her has pleaded guilty to her murder.

Mali Bennett-Smith, said his sister, 19-year-old Luka Bennett-Smith, had been “annoying” and he wanted to kill her.

He was sentenced to a minimum detention term of 10 years and five months after pleading guilty to her murder at Bristol crown court on Monday.

The court heard that Bennet-Smith, who was home-schooled, had an “unconventional upbringing” and would disappear into a world of video gaming and become disassociated from the real world.

Bennett-Smith told police that he had asked his sister if he could practise a headlock on her and she agreed.

But instead of letting go when she tapped him, as he had done on previous occasions, he continued to hold her before stabbing her repeatedly at the home they shared in the St Andrews area of Bristol on 20 October last year.

He rang the emergency services 20 minutes later, shortly before 6.30pm, and told them: “I stabbed my sister to death.”

The court heard that he had told operators they had not been having an argument, but said: “I hated her my whole life and I don’t know, I just didn’t want to ever see her again.”

In a prepared statement he later gave to police, Bennett-Smith said his sister, who had attention deficit hyperactivity disorder, was “annoying” and he felt she bullied him.

He told officers: “After watching a video, I went downstairs to the lounge and I asked Luka if I could practise a headlock on her.

“She agreed, we have done this before and when she needed me to stop we had an agreement where she would tap me on the arm.

“On this occasion I had decided I was not going to stop, I wanted to kill her, I had enough with regards she had been treating me over the years and recently.”

The court heard that Bennett-Smith had grown up on a remote farm in New Zealand, but after his parents divorced he moved to the UK with his sister and mother with the intention of going to college to prepare to join the army.

He later dropped out of his college course, the court was told.

Ray Tully KC, defending, said Bennett-Smith had severe dyslexia and dysgraphia and, that although he had an above average IQ, he was found to have below average “processing speed”.

He said his “somewhat unconventional” upbringing meant he did not mix with other children of his own age and spent a lot of time gaming.

Tully said he would disappear into a world of video gaming and become dissociated from the real world.

“Mali did not know how to manage his increasing feelings of frustration and resentment towards Luka,” he said.

Judge William Hart said: “It’s often said in courtrooms when a child has died: ‘It must be every parent’s worst nightmare’.

“The horror of the loss of their daughter at the hands of the son they still love is beyond even the worst nightmares.”

Sentencing him, Hart said: “The killing was shocking and brutal.

“It has deprived Luka of her life, your parents in effect of two of their children, and will deprive you of your liberty.”

The judge lifted reporting restrictions on naming the defendant after an application by the PA news agency.