Four people have been arrested by Brazilian police in connection with Sunday’s tragic events in Santa Maria. 

231 people, primarily aged between 16 and 20, perished in a fire at a freshers event at the city’s Kiss nightclub. The blaze started during a performance by pop band Gurizada Fandangueira after an onstage pyrotechnics display went dreadfully awry. Brazil is currently in a state on national mourning, with President Dilma Rousseff describing the event as a “tragedy for all of us.”

As BBC News report, four arrests have now been made over the incident. Gurizada Fandangueira singer Marcelo Santon has been taken in by police for questioning. Early reports suggested a flare was let off from the stage, which subsequently ignited foam insulation in the roof and sent toxic smoke cascading through the venue. Band guitarist Rodrigo Martins, however, claims that no flare was launched: “It might have happened because of the Sputnik, the machine we use to create a luminous effect with sparks. It’s harmless; we never had any trouble with it. When the fire started, a guard passed us a fire extinguisher. The singer tried to use it but it wasn’t working.”

The co-owner of the nightclub has also voluntarily submitted himself to the police, and another co-owner has been brought in for questioning. The venue’s head of security has also been held. Some survivors claimed that Kiss’ door security briefly prevented people from leaving the club. More than 50 of the victims are being buried on Monday.