A fire at an apartment building in Framingham, Massachusetts, may have been intentionally set, investigators said Monday.
Firefighters were called to the building at 1630 Worcester Road just before 4 a.m.
Video from the inside of the building shows doors and walls covered in black soot and hallway lights melted.
"I opened my door, it was like, it looked like Hell," said a tenant named Sandy. "You couldn't see anything, it was so thick."
Get Boston local news, weather forecasts, lifestyle and entertainment stories to your inbox. Sign up for NBC Boston’s newsletters.
She says her dog, Mocha, started barking, alerting her to the fire.
It started on the first floor in a lobby area of one of the buildings at The Green at 9 and 90 apartment complex early Monday morning.
"Like I was in a dream, and Satan was going to pop out," said Sandy.
Local
In-depth news coverage of the Greater Boston Area.
Tenants on the first floor say the smoke in the hallway was so thick, they couldn't escape and waited on their balcony in frigid temperatures until they got the all clear.
"I was going to get a facecloth and run down the hallway with my family," said tenant Donald Lyons. "Or throw a mattress off the balcony and jump like the 12 feet down, because we were, like, trapped."
Investigators aren't releasing details of what they found at the scene, but Framingham Fire Chief Michael Dutcher tells NBC10 Boston it's possible from the evidence they gathered that someone may have set the fire on purpose.
There are 200 apartments in the building, so a lot of lives could have been at risk.
"It could have been a mass casualty," said tenant Craig Lyons. "Especially how bad the smoke was."
Four tenants were taken to the hospital to be checked out for smoke inhalation. They were all treated and released.
"I don't feel safe here anymore," said Alicia Lyons, one of the tenants who was sent to the hospital. "I don't understand why people want to harm other people."
A $5,000 reward is being offered by the Arson Watch Reward Program for any information that leads to the person who may have started the fire. Tips can be called into 1-800-682-9229.
Get updates on what's happening in Boston to your inbox. Sign up for our News Headlines newsletter.
