Police in Brazil say 16 people will face criminal charges in connection with a deadly fire at a Santa Maria nightclub in January in which 241 people died.

Inspector Marcelo Arigony told a news conference police were seeking murder charges against the nightclub's two owners, their manager, and three band members, among others.

The lesser charge of manslaughter is being sought against several city officials for granting the club an operating permit.

Mr Arigony added that the mayor and fire chief of Santa Maria, the city where the fire occurred, could also be held responsible for the accident because of the negligent safety inspections of the nightclub.

But he said that because Mayor Cezar Schirmer is an elected official, the police cannot file charges against him and only the Rio Grande do Sul State Supreme Court and the city's legislature can determine if he is charged.

Only a military court can charge the fire chief, because the department is under the control of the police, which is part of the military.

The fire tore through the crowded, windowless Kiss nightclub in Santa Maria on 27 January, filling the air with flames and thick, toxic smoke.

Mr Arigony said the band performing at the club lit a flare, which ignited flammable soundproofing foam on the ceiling.

The cyanide, carbon monoxide and carbon dioxide released by the ensuing fire was what killed the people inside, he said.

"The smoke descended like a black mattress and people breathed that smoke, that was probably cyanide, and they started losing senses," he told the news conference.

The investigation showed numerous "irregularities", including flawed fire extinguishers, overcrowded of the building, and only one door leading in and out of the club.

Results of the investigation will be forwarded to state prosecutors, who will decide whether to file the charges sought by police.

The blaze began around 2.30am local time during a performance by Gurizada Fandangueira, a country music band that used pyrotechnics during their shows.

The band's guitarist said that the 615sq/m club was packed with about 1,200-1,300 people.

The police have said the capacity for a club of that size is less than 700 people.

Kiss apparently had no alarm or sprinkler system and only one working exit, leaving the crowd to search desperately for a way out.

About 50 victims were found in the club's two bathrooms, where they crowded after blinding smoke evidently caused them to believe the doors were exits.