Police freed as many as 400 captives, aged from six to 50, from the house in Kaduna in northern Nigeria in a raid on Thursday. Some were chained to radiators, tires or hub caps and others bore visible signs of scars from whippings and beatings.

More than a dozen, including 10 children, were hospitalized on Saturday. All the adults were in critical condition, with one vomiting blood.

Police set up a makeshift camp for the others at the edge of the city and were trying to register the freed captives. In one of the buildings at the camp, children queued to register their names against a list, later laughing and playing before being served a plate of noodles.

Outside, dozens of parents, faces contorted with worry, gathered to collect their children. Some had paid tuition fees to the men running the house believing it to be an Islamic school, while others viewed it as a correctional facility with no expectation of instruction.

Kaduna state police spokesman Yakubu Sabo said the “dehumanized treatment” they discovered made it impossible to consider the house an Islamic school.

Local media said some of the children had been tortured, staved and even sexually abused. Reuters was unable to immediately verify the reports.

Hafsat Mohammed Baba, the state’s commissioner of human services and social development, told Reuters a headcount had accounted for just 190 people, including 113 adults and 77 children. The reason for the discrepancy in numbers was not immediately clear, but authorities said some freed from the home fled immediately.

FREED CAPTIVES

Police raided the school after a relative was denied access to the captives. Seven people who said they were teachers at the school were arrested in the raid.

Police called on families from across the region, from the suburbs of Kaduna to the nearby countries of Ghana, Mali and Burkina Faso, to collect the freed captives. Despite the reports of abuse, some were reluctant to return home with their family members.

Mohammed Sani Abu Sha’aban, a father of 13 from the Kaduna suburb of Nasarawa, sent two of his sons – 16-year-old Salim and 25-year-old Jamilu – to the school for more than three years.

He paid 34,000 naira ($111) per term and said it had helped his sons, particularly Salim. “Now that they are set free, he may relapse into his past negative attitude of absconding from school and other vices,” Sha’aban said.

Islamic schools, known as Almajiris, are common across the mostly Muslim north of Nigeria. Widespread poverty prompts many parents to leave their children at the institutions, yet they have been dogged by reports of abuse and accusations that some children are forced to beg on the streets rather than get an education.

Some activists have called on the government to outlaw the schools.

But Sha’aban, who said he visited regularly and never saw signs of poor treatment, called on the state to keep the Kaduna school open. “The closure of the school is really a source of concern and very disturbing to us who have unruly children and wards,” he said.