Around 40 police officers intervened in a healing ceremony in a home on Nieuwstraat in Eersel, Noord-Brabant, on Wednesday evening. A few weeks ago a 31-year-old man from Hungary died after participating in a similar ceremony. Four people were arrested on Wednesday, the Telegraaf reports.

A total of 16 people attended the healing ceremony. The attendees who were not arrested were taken to another location.

The police launched an investigation after the Hungarian man was found dead in his home in Eindhoven a few weeks ago, according to the newspaper. The police believe the man used Ayahuasca during a healing ceremony before his death. Ayahuasca contains dimethyltryptamine (DMT), which is listed as a hard drug in the Opium Act. According to addiction clinic Jellinek, Ayahuasca is a South American hallucinogenic beverage.

During the investigation, the police determined that the organizers of the healing ceremonies were advertising them on the internet. Participants were given a specific location only at the last moment. When the investigators found out that a ceremony was planned for Wednesday evening, the police decided to intervene. They raided the Eersel home before the Ayahuasca was used, the Telegraaf writes.

A 33-year-old Spanish man and a 38-year-old Italian woman were arrested on suspicion of organizing the healing ceremonies. A 47-year-old Spaniard and a 25-year-old Italian were also arrested on suspicion of involvement. The suspects are in custody for questioning and further investigation. More arrests may follow.

According to Eindhovens Dagblad, the company in Eersel that organizes the retreats is registered in the name of a Colombian woman. The international company always held gatherings that lasted up to four days, with participants deciding themselves how many of the days they wanted to participate. The days consisted of different meals and an overnight stay, except for the sessions with Ayahuasca, according to the newspaper. Participants paid 240 euros for a day and a night, or 800 euros for four days.