SANTA MARIA, Brazil — The bodies of the young college students were found piled up just inside the entrance of the Kiss nightclub, among more than 230 people who died in a cloud of toxic smoke after a blaze enveloped the crowded locale within seconds and set off a panic.

Hours later, the horrific chaos had transformed into a scene of tragic order, with row upon row of polished caskets of the dead lined up in the community gymnasium in the university city of Santa Maria. Many of the victims were under 20 years old, including some minors.

The first funerals of victims were planned for today.

As the city in southern Brazil prepared to bury the 233 people killed in the conflagration caused by a band’s pyrotechnic display, an early investigation into the tragedy revealed that security guards briefly prevented partygoers from leaving through the sole exit. And the bodies later heaped inside that doorway slowed firefighters trying to get in.

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

Survivors and another police inspector, Marcelo Arigony, said security guards briefly tried to block people from exiting the club. Brazilian bars routinely make patrons pay their entire tab at the end of the night before they are allowed to leave.

“It was chaotic and it doesn’t seem to have been done in bad faith because several security guards also died,” he told The Associated Press.

Later, firefighters responding to the blaze initially had trouble entering the club because “there was a barrier of bodies blocking the entrance,” Guido Pedroso Melo, commander of the city’s fire department, told the O Globo newspaper.

Police inspectors said they think the source of the blaze was a band’s small pyrotechnics show. The fire and toxic smoke created by burning foam insulation material on the ceiling engulfed the club within seconds.