BENSONHURST - (AP) - A suspicious fire tore through a building thathoused Guatemalan immigrants, gnawing gaping holes in thestructure's backside, partially collapsing the roof and killing atleast five people.

The early Saturday morning blaze at 2033 86th St. in Bensonhurst is beinginvestigated as a possible case of arson because it started behindthe door of the first-floor entrance to the building, New York CityFire Commissioner Salvatore Cassano said.

"That's not where a fire would normally start," Cassano saidafter surveying the devastation of the fire, which trappedresidents and caused the interior walls to collapse. "That's whythis is a fire that we are saying is very likely to beincendiary."

Four people in the building were injured, including an infantand a child who were tossed out the window by a woman franticallytrying to save them. The infant was in critical condition with afractured skull after bystanders below failed to catch him,officials and witnesses said. The other child landed on an awning.

At least one adult was hospitalized, and 13 firefighters wereinjured, none of them seriously, officials said.

The fire started at about 2:30 a.m. and flames quickly engulfedthe three-story building on a busy commercial strip, consuming aground-floor Japanese restaurant and two apartments on the upperfloors. The stairwell between the floors collapsed, as well as partof the roof, trapping residents, according to fire officials.

As the fire raged, a woman held a baby boy out a third-floorwindow. Bars covered the lower half of the window, keeping thewoman from climbing out, neighbor Juan Gabriel told The New YorkTimes.

"She was screaming, 'Help me, help me,' " Gabriel said.Moments later, she threw the infant out the window to Gabriel andtwo other men.

In the darkness, the child fell to the ground, authorities said.She then tossed another child out the window. He landed on theawning below.

It wasn't immediately clear whether the woman survived the fire.

The fire was the deadliest in the city since March 2007, when 10people from two Malian immigrant families, including nine children,were killed in the Bronx. Seventy-three people died in fires in2009, the fewest number of fatalities recorded in more than 90years.

Hours after the fire, in the Bensonhurst neighborhood near therumble of an elevated subway, residents said they were shocked bythe carnage and destruction.

Alex Lazaro, a Mexican man who works as a union organizer andlives in the neighborhood, said that the people who lived in thebuilding were poor immigrants.

"They live very humbly and don't make enough to live in abetter place," Lazaro said, standing on a sidewalk looking at theburned-out shell of the building, which was cordoned off.

Most of the building's residents were from Guatemala, Gabrielsaid.

For decades, the neighborhood was traditionally home to Italiansand Jews, but in recent years immigrants from Russia, China andLatin America have moved in, residents said.

Hazel Deleon, who until recently worked at a health food storeseveral doors from the building, said she was walking by thismorning and stopped and "freaked out."

A lifelong resident of the neighborhood, she said immigrants inthe building were packed together into the apartments.

"I would see them looking out the windows when I passed by,"she said.