An arsonist struck at the vacant woolen mill in Sanford on Monday morning.
The fire at the International Woolen Mill was reported about 9 a.m., according to Shannon Moss, a spokesperson for the Maine Department of Public Safety.
When firefighters arrived, they discovered heavy smoke and flames in a portion of the long-vacant mill complex, Moss said Thursday morning.
It took crews several hours to get the flames under control.
No one was injured in the fire.
The Maine fire marshal’s office has ruled the fire an arson.
The fire remains under investigation.
