A father was arrested on Wednesday after his 21-month-old son tested positive for methamphetamine at a Kowloon hospital.

The 25-year-old man, surnamed Ching, who is reportedly an engineer, was arrested at Kwong Wah Hospital in Kowloon after medical staff found his son tested positive for the illegal drug, Sing Tao Daily reported.

It was understood that Ching’s mother took the baby to a child health center for a regular check-up in late July. There, health center staff discovered that the boy’s urine tested positive for methamphetamine, and transferred the baby to Kwong Wah Hospital for a detailed examination.

Hospital staff reported the case to the police.

When police officers requested that the baby’s parents go to the hospital for questioning, only the father showed up.

The father denied that he and his wife, a 30-year-old woman surnamed Lee, abused illegal drugs.

However, officers found the man suspicious and arrested him for alleged ill-treatment or neglect of a child or young person.

Officers are now hunting for the baby’s mother. The child remains in hospital for medical treatment.

Paediatrics specialist Dr Wilson Fung Yee-leung said that a 21-month-old baby might inhale meth if the people taking care of him used the drug nearby. He added that exposure to the powerful drug could damage the development of a baby’s brain.