As fire investigators worked on the cause of the blaze, officials were also trying to sort out the status of the home, which they initially described as a "group home" or "halfway house."
"[Investigators] have not ruled anything out," Utica Fire Chief Russell Brooks told the Utica Observer-Dispatch. "We've received a lot of conflicting information which doesn't really correspond with how the flames traveled and the intensity of the fire.
Brooks said investigators were looking into whether the two-story home should have been licensed by regulatory agencies. He said the city has an inspection program that requires every rental dwelling to undergo a fire safety check, but that the home had not been inspected for at least several years.
"Somehow this building went under the radar. It had a different classification. It was classified in with hotels and motels and it definitely wasn't that," Brooks said.
The house had some smoke detectors and investigators were checking whether any were working.
"They were not in every bedroom as they were required to be and some of the ones that were there were not operating. The batteries were dead," Brooks said.
Brooks said state arson investigators were traveling from Albany to assist in the investigation.
"We don't have a clear indication of how it started. We are getting a lot of conflicting information so we are not going to leave any stone unturned. We are going to be very thorough with the investigation," he said.
Firefighters pulled three people out of the burning house. Two of them died at a Utica hospital, while the third was taken to Upstate Medical Center in Syracuse with severe burns.
The other two bodies were recovered after firefighters brought the fire under control, he said.
The fire was called in at 10:38 p.m. Tuesday and firefighters found heavy smoke and flames coming from the building when they arrived, Brooks said.
Utica Public Safety Commissioner Daniel LaBella said one person jumped from a second-floor balcony and was taken to a hospital. He said the owner of the house reported that seven people lived on the second floor and two lived on the first. But Brooks said as many as 12 people may have been living in the house.
Authorities said they would release the names of the victims after their families were notified.
"I'm just devastated," said Donna Marano, who owns the house. "I've been doing this for 23 years. These people are like family to me."
"It's a tragedy; it's a sad day. I'm sure the firefighters did everything they could," said Utica Councilman James Zecca.
Residents Wayne Clulo and Tom Kozdra said they heard an explosion inside the house as they were escaping, but Brooks said Wednesday it wasn't yet clear there was an explosion or what role it might have played in the fire.
The Mohawk Valley had not seen a more deadly fire since December 1991, reports the Observer-Dispatch.