Brazilian police arrested four men Monday in connection with the tragic nightclub fire in Santa Maria that killed 231 people on Saturday night. The two club owners and two band members have not been charged yet but are expected to be detained and questioned for five days as investigators piece together what happened.

Most of the people killed in the fire suffocated from toxic fumes that quickly filled the Kiss club after the band set off pyrotechnic flares around 2:30 a.m. Sunday, according to Reuters. One band member was killed in the fire. Police said club security guards tried to stop some of the fleeing patrons because they hadn’t paid their bar tabs.

“It was terrible inside – it was like one of those films of the Holocaust, bodies piled atop one another,” police inspector Sandro Meinerz told USA Today. “We had to use trucks to remove them. It took about six hours to take the bodies away.”   

Firefighters and partygoers used their shirts to cover their faces from smoke as they tried to pull people away from the building. Many young men helped emergency officials by breaking windows and wielding axes to hack through barriers separating the injured from the outside.

When the flare hit the ceiling, one of the band members tried spraying it with water and a bouncer used a fire extinguisher, both to no avail. The New York Times reported the extinguisher didn’t work, perhaps one of the reasons the club’s operating license was up for review after it expired last year.

“No one cared because they always do that, to make us dance a little harder,” one survivor said. “I started screaming, and thought, ‘When it’s your time to go, it is God who decides.’”

Investigators will try to find out if negligence was the true cause of the shocking death toll, already the popular opinion of some who were present.

“I don’t think there was an emergency exit,” said Fernanda Bona, who was taking pictures of the concert when the fire began. “We didn’t know what was happening inside. It happened in five minutes, not even. Five minutes after I got out, I saw a lot of panic and lots of people trying to get out.”

Funerals have been planned throughout the week in Brazil but were already under way with a large procession in Santa Maria on Monday. The death toll was revised from 233 to 231 but more than 100 people were injured in the blaze, approximately 73 of whom were still hospitalized days afterward.

The owners of the club took to their Facebook page to announce, “We would still like to reiterate that our staff has the highest technical qualifications and was properly trained and prepared for any contingency.”