Two people have been charged in Norway for breaking into an underground bunker in Oslo, the scene of a rave where about two dozen people accidentally suffered carbon monoxide poisoning at the weekend.
Police in the Norwegian capital said on Monday they were considering whether more people should be charged and if other charges should be added for the two facing the trespassing penalties.
The incident came to light early on Sunday when a police patrol happened upon a group of party goers near the bunker. Several were dizzy and incoherent, triggering a large response from the authorities.
Up to 200 people reportedly attended the party, police wrote on Twitter.
The police probe has involved checking online traces and questioning witnesses, the police statement read.
Forensic technicians were due on Tuesday to investigate the bunker.
Police and fire services earlier said they suspected the poisoning was caused by portable generators used to power audio systems.
Meanwhile, Oslo University Hospital said that three of the 27 people admitted on Sunday remained under observation or in intensive care.
Five of the patients had been in serious, but not life-threatening, condition.
Most of the patients admitted were partygoers, but two police officers were also treated at the hospital.
Carbon monoxide is a colourless, odourless gas which replaces oxygen in the blood when inhaled and continues to inflict damage even after the victim returns to clean air.