The nightclub fire that claimed more than 230 lives in the Brazilian city of Santa Maria may have been caused by cheap flares used there by a band and "diverse irregularities" in the club itself, according to the police.
The revelation came as the Rio Grande do Sul state forensics department raised the death toll from 231 to 234 to account for three victims who did not appear on the original list of the dead.
"The flare lit was for outdoor use only, and the people who lit them know that," Marcelo Arigony, police inspector, said, adding that members of the group acknowledged regularly opting for the less expensive flares.
"They chose to buy those because they were cheaper than those that can be used indoors."
Flares meant for outdoor use cost a mere $1.25 a piece, compared with the $35 price tag for an indoor flare.
Authorities say more than 120 people remain hospitalised for smoke inhalation and burns, with dozens of them in critical condition.
Those who survived Sunday's fire were brought to three hospitals in Santa Maria and to Porto Alegre, capital of Rio Grande do Sul, Al Jazeera's Gabriel Elizondo said.
Malfunctioning fire extinguisher
In addition to the use of outdoor flares, police said the Kiss club's ceiling was covered with insulating foam made from a combustible material that appeared to have ignited after it came in contact with a spark from a flare lit during the performance.
The fire extinguisher also malfunctioned, allowing the blaze to spread throughout the packed club at lightning speed, emitting a thick, toxic smoke.
Al Jazeera's Gabriel Elizondo reports on mourners' calls for justice following deaths from the blaze
Because Kiss apparently had neither an alarm nor a sprinkler system and only one working exit, the crowd was left to search desperately for a way out.
In the initial confusion, the security at the club, who may not have been aware of the fire, reportedly shut down the main entrance to prevent the crowd from leaving without settling their bar tabs, our correspondent said.
About 50 of the victims were found in the club's two bathrooms, where the blinding smoke caused them to believe the doors were exits.
Arigony - whose cousin died in the fire - said people headed towards the bathrooms because the only lights in the dark club were coming from there, and the patrons mistook them for exits.
The foam, which emitted a toxic gas, was not proper soundproofing equipment and was likely only used to cut down on the echo inside the club, he said.
He said a full analysis of the foam was under way.
The malfunctioning fire extinguisher was not legal, he said, and the club's operating licence had expired in August.
"There were diverse irregularities," Arigony said. "Any child could have seen that this establishment should not have been open."
The blaze started at around 2:30am local time, during a performance by Gurizada Fandangueira, a country music band that made the use of pyrotechnics a trademark of their shows.
The band's guitarist told media that the 6,650sq ft club was filled with an estimated 1,200 to 1,300 people.
The police have said the capacity for a club of that size is 700.
Outraged locals, mostly young people like those who died in the blaze, marched through Santa Maria to demand justice for the dead, an unusual move in a country where public protests are rare.
The fire inspired nationwide action, and several mayors said they would crack down on nightclubs and other venues in their cities.
No charges have been filed. Under Brazilian law, prosecutors can only file charges after police complete their investigation, which in this case could take 30 days.
Prosecutors have said manslaughter charges could be filed.