In a statement, Kota Setar district police chief Ahmad Shukri Mat Akhir said the woman, aged 31, was picked up yesterday at 5.30pm for questioning.

This follows the arrest of the stepfather earlier yesterday.

Both suspects have been remanded until May 5.

Shukri said the man had tested positive for methamphetamine.

Police had launched an investigation into the abuse case following a report lodged by the Alor Setar social welfare department (JKM).

The elder sister’s teacher had spotted bruises on the victim’s face and other parts of her body on Tuesday morning.

On questioning, the victim revealed she had been beaten by her stepfather.

The teacher then reported the matter to the school administration before it was referred to the JKM.

The two sisters, studying in Year One and Three, are currently warded at the Sultanah Bahiyah Hospital for follow-up investigations and treatment.