CNN  — 

In Benin, when children fall sick, their parents often turn to voodoo. The West African nation is, after all, its spiritual home. Officially a state religion since 1996, Voodooism is practiced by 17% of the population, with many outside of the religion professing a cultural link to some of its rituals.

But what happens inside the hundreds of facilities dotting the country is a mystery to most outsiders. Now advocates are raising the alarm saying the facilities may harm the children they aim to help.

Djofin Assou Gilbert is an advocate for children in Benin. He first became concerned about the practices inside the convents in early 2015, when he noticed a group of children standing outside a convent.

“It was the middle of the day and the children weren’t wearing their school uniform,” he remembers. “I wanted to know why they weren’t in school. I tried to ask a little girl why she was there, but she couldn’t answer.”

The girl, he says, had lost her mother tongue.

“I was desperate to find out more. Like many people in Benin I’d heard of these convents, but I didn’t know what was happening inside.”