TAIPEI • A Taiwanese man who decapitated a four-year-old girl in public on a busy Taipei street a year ago was yesterday sentenced to life in prison for what the court called an appalling crime.

Wang Ching-yu, 34, had pleaded guilty to killing the child nicknamed "Little Lightbulb" in a crime that shocked the generally peaceful island. Prosecutors had called the crime "extremely cold-blooded" and sought the death penalty.

But judge Tsai Shou-hsun told a Taipei district court that Wang would instead be jailed for life as he had a "mental handicap".

Wearing black-framed glasses, a white T-shirt and track pants, with his head shaved, Wang remained expressionless as he listened to the verdict, responding: "I understand."

The victim's family did not release a statement following the verdict.

In the gruesome crime in March last year, Wang had grabbed the child from behind and decapitated her with a cleaver as she was riding a bicycle.

The mother, Ms Claire Wang, was about 1m away from her daughter but could not stop the killer. She said she had thought the man was approaching to help lift her daughter's bicycle.

Wang was subdued by passers-by and later arrested at the scene of the crime. Police said he had previously been arrested for drug-related crimes. He was attacked by an angry mob while in custody.

In a statement after the verdict, the court said the decision was in accordance with international human rights covenants protecting those with mental illnesses.

It said Wang had been expelled from school and had gone through drug rehabilitation, but was reclusive and isolated, developing schizophrenia and hallucinations.

However, the statement also described the killing as "grotesquely violent", adding that Wang had known murder was illegal and had dodged supervision in order to commit it.

"He has not shown empathy and regret, and after assessment, the chance of committing crime again is still high," the statement said.

After the killing, the victim's mother had criticised death penalty advocates for using her daughter's death to advance their cause.

Speaking to the media just hours after witnessing the killing of her child, Ms Wang, who has three other children, called for calm and reason.

"I believe the suspects in these kinds of random killings lose their minds at that moment," she said.

"This is not a problem that can be solved by passing a law," she added. "I hope we can address the problem from its root, from the perspective of family and education, so that there will no longer be people like him (the perpetrator) in our society."

Taiwan resumed capital punishment in 2010 after a five-year hiatus. Executions are reserved for serious crimes such as aggravated murder.

Some politicians and rights groups have called for its abolition, but various opinion surveys show majority support for the death penalty.

After the shocking decapitation, hundreds of Taiwanese, many dressed in black and wearing stickers reading "Death penalty is necessary", called for Wang to be executed.

The killing came less than a year after the throat of an eight-year-old girl was slit in her school restroom in Taipei. It sparked widespread public anger and fresh debate about capital punishment.

AGENCE FRANCE-PRESSE. CHINA POST/ASIA NEWS NETWORK