Teenager murdered sister after telling her he wanted to practise a headlock

A teenager who stabbed his older sister to death after telling her he wanted to practise a headlock on her has been sentenced for her murder.

Mali Bennett-Smith, 17, told police his sister 19-year-old Luka Bennett-Smith was “annoying” and he wanted to kill her.

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

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

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

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.”

The court heard that Bennett-Smith grew up on a remote farm in New Zealand, where he was home-schooled, but after his parents divorced he moved to the UK with his sister and mother with the aim of going to college to prepare to join the Army.

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

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.”

Sentencing him to detention during his majesty’s pleasure, the judge 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.”

He said the use of a knife, the fact Bennett-Smith “undoubtedly intended to kill” and the brutality were aggravating features.

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

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

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

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

He said the teenager, of Cromwell Road, had “genuine remorse” for his actions.

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

After the sentencing, Detective Inspector Nadine Partridge of Avon and Somerset Police said: “Our thoughts remain fully with Luka’s family at this difficult time. They continue to be updated and supported by specially trained family liaison officers.”