A 31-year-old Hong Kong mother was jailed for eight years by Hong Kong’s High Court on Thursday over the 2015 manslaughter of her three-month-old son.

Though psychological reports showed that Leung Siu-fong was of below-average intelligence, she should still be capable of telling right from wrong, Judge Esther Toh said, according to Metro Daily.

The judge also noted that there were few mitigating factors calling for leniency, given Leung was in a middle-class family environment with support from her husband, mother and sister. The tragedy could only be explained by her adjustment disorder and depression.

As a parent, Leung had a moral and legal duty to protect her son, Toh said. Given the multiple severe injuries sustained by the baby, Leung’s abusive assaults must have happened on more than one occasion, the judge said, adding that no punishment could bring back the boy’s life.

Read: Cheung Chau mother guilty over death of baby son