Buildings Commissioner Robert LiMandri said Friday that the Brooklyn building that was the site of last month's deadly fire had illegal subdivisions that should never have been built.

An investigation found the third floor of the Bensonhurst apartment, had a two-bedroom unit that had been converted into four separate residential units.

The building owner was issued three violations.

Five people were killed, including Luisa Ordoñez de Chan, right, a Guatemalan immigrant who died after throwing her two young children to safety.

Daniel Ignacio, 27, a resident of the building, was arrested and charged with murder and arson.

Police sources say Ignacio told authorities he was drunk when he doused a roll of toilet paper with paint thinner, lit it on fire and threw it into a baby carriage near the building's front entrance.

He later helped a two-year-old boy escape the fire.