RIO DE JANEIRO - Brazilian police on Wednesday found more breaches in a nightclub blaze that killed more than 200 people over the weekend, including unauthorized renovations that may have contributed to the fire.

Jader Marques, the lawyer of the nightclub owners, said his clients renovated the building without informing local authorities and, in particular, installing sound-proofing foam on the ceiling after neighbors continued to complain about noise. The project was not approved by fire inspectors.

Sunday's fire appears to have started when the band lit a flare that ignited the flammable foam boards, releasing toxic smoke that choked many of the victims.

That irregularity is among a long list of possible causes such as overcrowding, lack of an emergency exit and the malfunction of extinguishers.

Two band members and two club owners were detained Monday on temporary arrest warrants. Police suspect the owners of attempting to tamper with evidence of their negligence, including security camera footage and the cash register, which could show how many people were inside the club at the time.

The fire at the Kiss nightclub in south Brazil's college town of Santa Maria, Rio Grande do Sul state, killed 235 people, according to the latest report from the authorities.

Currently, 143 people remain hospitalized with fire-related injuries, and at least half of them are in critical condition.