Prosecutors in southern Brazil are investigating whether city leaders and inspectors were negligent in allowing a club where 235 people died in a fire last week to operate.

The investigation is separate from a criminal probe into the causes of the tragedy at the club in Santa Maria.

It comes after police said the club's sole exit was partially blocked and that fire extinguishers and emergency exit lights were not working.

Investigators said the lapses led to the stampede and subsequent trampling and suffocation that killed most of the fire's victims in the Kiss nightclub.

"There is a political dimension to what happened," said Cesar Augusto Carlan, a public prosecutor for the state of Rio Grande do Sul, where the fire occurred.

He said the investigation sought to determine what fault may lie with the city, fire inspectors and any other enforcement officials who had allowed the nightclub to operate.

Police officials have already begun laying some of the blame on local authorities and an overall culture of lax enforcement in Brazil.

"What we can tell, empirically, is that everything is out of order," said Marcelo Arigony, the police chief in Santa Maria.

"The question of the permit, inspection by the fire department, all of that is the responsibility of local administration."

"And it's not just here, it's Brazil," he added, noting the rampant violations uncovered in recent days as local officials nationwide sought to crack down on irregularities at nightclubs and other venues in the fire's aftermath.

In a news conference on Tuesday, Santa Maria Mayor Cesar Schirmer said city inspectors visited Kiss nightclub in April after it had undergone remodelling and found no reason to revoke its operating permit.

He said his mind was "at ease" that city hall had "fulfilled its obligation".

Mr Schirmer added: "The establishment, in our view, had no irregularities. If any measures or inspections should have been taken, that was the responsibility of the fire department."

The local fire department, for its part, reiterated in a statement that it was in the process of renewing the club's safety permit when the fire occurred, but that the establishment was authorised to operate in the meantime.

It added, however, that the club appears to have committed several safety violations, noting that it did not have a permit allowing the pyrotechnics that sparked the fire and that regulations required the exit to be unobstructed, which was not the case.

"If there had been a request to use pyrotechnics in the nightclub Kiss, the fire department would not have authorised it," the statement read.

Meanwhile, police have said one of the club's owners, who with his co-owner is in police custody for questioning, tried to take his own life on Tuesday.

The owner, identified by police as Elissandro Spohr, told officials he could not bear the strain of the tragedy.

In addition to the two club owners, two members of Gurizada Fandangueira, the band that was performing at the club, are also in custody for questioning.

Authorities aim to extend their detention beyond an initial five days, according to lawyers.

One of the band members, police say, lit an outdoor flare during the show, igniting overhead soundproofing material from which the fire rapidly spread.

Mr Arigony said the investigation would still take weeks, but that criminal charges are sure to follow.

The musician who lit the flare, he said, will face at least a charge of manslaughter.

Local authorities have revised the death toll from the tragedy to 235, following the death of a man in hospital and a recount of the confirmed dead.

As of yesterday afternoon, 140 people remained in hospitals, 82 of them on respirators.

Some of those being treated are suffering complications from the toxic chemicals inhaled during the fire.