Malaysian police said they have arrested hundreds of suspects as part of an investigation into child abuse at care homes run by an Islamic conglomerate.

In what is believed to be the worst such case to hit the country in decades, police said on Saturday they had arrested 355 people, including religious studies teachers and caregivers, and rescued more than 400 children.

At the heart of the investigation is the Global Ikhwan Service and Business (GISB) group, which has long been controversial for its links to the banned Al-Arqam sect.

Police said they had arrested GISB leader Nasiruddin Ali along with 30 other members of the group after carrying out raids on scores of premises, including charity homes, businesses and religious schools.

On Tuesday, Malaysia’s police chief Razarudin Husain said authorities had frozen 96 accounts linked to the group containing approximately $124,000 and seized eight vehicles.