A thin mist hangs in the air as a handful of troubled souls wander aimlessly around the Bouya Omar mausoleum in central Morocco, the occasional chilling cry rising from behind its walls.
These are Morocco's "possessed" - from violent schizophrenics to hard drug users - who are believed to be tormented by evil spirits and whose relatives bring them here to await deliverance.
But many are left wondering exactly what goes on inside the sanctuary of the 16th-century Moroccan saint, situated in a small town named after him on the plains east of Marrakesh.
Bouya Omar's followers claim the mentally ill are healed by the saint's supernatural powers, but rights groups allege gross mistreatment of those taken there, with one former inmate describing months of "hell".
Activists say hundreds of people have been kept in chains here, sometimes starved and beaten, making the place a byword for cruelty and highlighting the stigma attached to mental illness in Morocco.
Their numbers cannot be verified and officials are reluctant to speak about what they say is a "sensitive subject".
Mohammed, a former drug addict from Tangiers, is adamant that he was subjected to brutal treatment seven years ago.
Taken to Bouya Omar by his brother in 2006 to be cured of his "demon", he says he was shackled and beaten repeatedly, given barely enough food to survive and robbed of the little money he had.
"I lived in hell for a year," Mohammed told AFP, adding that the experience had left him partially blind in one eye.
He says his brother eventually returned and "saved" him.
Damning reports about mistreatment, including one presented by a human rights organisation to the UN group on arbitrary detention visiting Morocco in December, prompted the health minister to announce that he would close Bouya Omar immediately - if only he could.
"I'm going to do everything I can to get this centre closed. Unfortunately the decision is not for the ministry of health," Hossein El Ouardi said in January.
The issue touches a sensitive nerve running through Moroccan society.
Popular beliefs abound in the Muslim country, about good and bad genies ("jnun") capable of affecting one's daily life, and the power over them of marabouts, holy men like Bouya Omar, whose ubiquitous white tombs are credited with the same supernatural forces.
Over the past decade, sociologists say, King Mohammed VI has encouraged such popular Islamic beliefs, commonly linked in Morocco to the world of healing, partly as a way of countering extremist ideology.
Despite the human rights violations now associated with it, the cult of Bouya Omar falls squarely within this tradition.