A French couple who allegedly wanted to “sacrifice” their five-year-old child in the Sahara were arrested in Spain at the end of December and are expected to be extradited to France, the authorities of the two countries announced.

The two music teachers from southwestern France were arrested on December 21 in the southern Spanish city of Algeciras while waiting to board a ferry to Tangier, Morocco.

The two parents, who, according to Spanish police, suffer from “psychiatric problems” and had a European arrest warrant issued against them for “abduction of a minor”, intended to kill their son in the Sahara, because they believed he was “possessed” and planned to “sacrifice” him.

The father and mother, aged 39 and 30 respectively according to the Bordeaux prosecutor’s office, are from Carcan, a village northwest of this French city, Patrick Meffran, the mayor of the small community, told AFP.

They were “fully integrated” into the community and had even established a conservatory and had more than 250 students, he said, explaining that he was “surprised” to learn of their arrest.

A source close to the investigations said the family left Karkan on December 16, in a 4×4 vehicle they had recently bought, after subletting the apartment where they lived.

Authorities began investigating the case on Dec. 19 when they received a call from a “person of interest” who said he was concerned about the 5-year-old son of a couple of friends.

The father “was delirious,” according to the prosecutor’s office, which opened a preliminary investigation into “kidnapping or arbitrary detention of a hostage under the age of 15 with the aim of facilitating the commission of a crime.”

Authorities are looking into the possibility that the parents may have belonged to a sect, but “it is still too early” to say for sure.

The mayor of Karkan said that last fall, during a storm, the father was found “naked in the woods and talking incoherently.” He was then admitted for observation in a psychiatric clinic. But he added that the two arrested “had the behavior of good parents, tender, very attentive”, towards their child, who was not yet attending school.

The couple remain in custody in Algeciras and their son has been taken to a juvenile detention center near that city. The prosecutor’s office said that their extradition process is ongoing while the process of returning the child to France is on its way to completion.