Firefighters from several towns responded to a four-alarm fire on Hale Street in Fitchburg on Friday night.
The fire was reported just before 5 p.m. and put out just before 7 p.m.
Heavy smoke and flames could be seen coming from a gaping hole in the roof and on all three floors of the building.
The Sentinel and Enterprise reports that the building was vacant. They say it was known as a place often occupied by the homeless, but it is currently unknown whether or not anyone was inside at the time of the fire.
A home next door also caught fire after a wall collapsed onto it.
There is no word on what caused the fire.
This week has been a busy one for firefighters across the state. Fire crews responded to three four-alarm fires in Barre, Lowell, and Lawrence on Thursday. A woman was killed in the Barre fire.