Brazilian police have arrested two members of a band that used ill-fated pyrotechnics during a performance at a student nightclub where 231 people died in a fire.
The band, called Gurizada Fandangueira, was performing at the overcrowded Kiss club when the fire started early on Sunday morning in the southern city of Santa Maria.
The nightclub's co-owner, Elissandro Spohr, was also detained by police over the blaze, Ms Sphor's lawyer told local media.
Police have also issued an arrest warrant for another owner of the club.
Inspector Ranolfo Vieira Junior said the arrests were for investigative purposes and that the trio can be held for up to five days.
Police said they think the pyrotechnics used by the band ignited sound insulation on the ceiling, and witnesses said a flare or firework lit by the musicians started the blaze.
In comments to the media, a band member has denied responsibility, while the club insisted in a statement that everything had been in order at the venue.
One member of the band, the accordion player Danilo Jacques, 28, was among the dead. Mr Jacques had escaped the burning building, but he died when returned inside to save his accordion.
The five other members of the band made it out safely.
The band's guitarist Rodrigo Martins said: "[The fire] 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."
Martins said the musicians were already receiving hostile messages.
"People on the social networks are saying we have to pay for what happened," he said.
"I'm afraid there could be retaliation."
Santa Maria is a university town and many of the 231 people who died and 117 injured were under 20 years old.
Officials have revised the death toll from 233 to 231 and said at least 100 others remained in hospital - 80 of them in serious condition.
It has also emerged that security guards tried to block people from leaving the club, according to survivors. 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," police inspector Marcelo Arigony said.
There was only one working exit at the club that was packed with some 1,500 people. A preliminary investigation also found that the exit was blocked by the bodies of those already dead.
During the fire, shirtless young men joined firefighters using axes and sledgehammers to pound at windows and pink exterior walls to free those trapped inside.
"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."
The bodies of the victims were lined up in a community gym, as desperate family members identified their relatives.
Funerals and collective wakes for some of those killed were held on Monday in Santa Maria.
Brazilian President Dilma Rousseff flew back from a summit in Chile and declared a national three-day mourning period.
"We are going to make it through this tragedy," Ms Rousseff said.
An event scheduled for Monday to mark 500 days to go until the 2014 World Cup in Brazil was scrapped out of respect for the victims.