Investigators say police have surveillance video of a man with a gas can in front of the building just before the fire started.
The fire was reported at 4:28 a.m. Monday inside an apartment building at 55 Harrison Place.
There was almost nowhere to go to escape. It was dark and smoke filled the first floor within minutes. Flames poured from the roof by the time firefighters got there.
People were jumping out upper floor windows, officials said. Others were scrambling down the back fire escape.
"She was my baby. My baby. And someone took her away," cried Antonio Olivo, who's 17-year-old daughter Sophia was trapped and killed in this fire.
Her friend, Leah, was burned over half her body trying to save her. Mr. Olivo, who remained at the scene all morning, is unable to wrap his head around the possibility that this fire was arson.
"My daughter is dead. She had nothing to do with anything," he said.
Firefighters said the flames spread incredibly fast, evidence of an accelerant. Fire Marshalls were looking at an orange gas can found nearby as possibly the one being held by a man seen on surveillance tape going in and out of the building before the fire.
Residents are also angry because they said they had complained about the condition of the building for months.
"The conditions were very bad. There were holes in the floor, the staircase was in very bad shape. We had to put portable liners on the floor and on the staircase," said FDNY's Chief Mannix.
"It's sad a 17-year-old girl had to die for these people to fix this building....That's no living condition for a child to live in, trust me" that resident said.
More than a half-dozen people suffered minor injuries and are in the hospital. Two firefighters were also treated.
The father of the girl who died says he is just lost.
"She couldn't wait until she was 18, so she could work or -- like any other teenager," Olivo said.
If the fire is confirmed as an arson, the other question is motive.