This general view shows the High Court building in Hong Kong on Aug 17, 2017. (ANTHONY WALLACE / AFP)

Condemned for their “extreme cruelty”, a Hong Kong couple on Tuesday were sentenced to life imprisonment after murdering their 5-year-old daughter in 2018 in one of the city’s worst child abuse cases in recent years.

The High Court also ordered them to serve a concurrent 9.5-year jail term for abusing their children – the girl who died of sepsis on Jan 6, 2018, and her 8-year-old brother.

The girl’s 56-year-old step-grandmother was also jailed for five years on two counts of child cruelty, for neglecting the children while they were being abused for over five months starting August 2017

A seven-member jury had unanimously convicted the children’s 29-year-old father, a transport worker, and their 30-year-old stepmother, a housewife, by a vote of six to one.

The girl’s 56-year-old step-grandmother was also jailed for five years on two counts of child cruelty, for neglecting the children while they were being abused for over five months starting August 2017.

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The girl was believed to have been repeatedly thrown high towards the ceiling of their flat and her wounds got infected the day before she was rushed to the hospital where she was declared dead. Both she and her brother were found with more than 130 wounds on their bodies.

The children lived together with their father and stepmother, as well as the biological daughter of the mother, who was not abused. They moved to their step-grandmother’s residence in 2017.

Slippers, scissors and a half-meter-long rattan stick were used to assault the children, according to a display by police. The children also suffered starvation.

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Handing down the sentence, Justice Albert Wong Sung-hau said the case involved “extreme cruelty”, inflicting severe physical and psychological harm on the two children.

The couple had never brought the girl to the doctor, while the step-grandmother, who could have been the “only hope” for the kids, also failed to do so, Wong ruled. The couple also tried to conceal the injuries when asked by schools.