NORTON, Mass. (WPRI) ─ Police in Norton are trying to determine whether the fire at a vacant mill building Wednesday evening was accidentally or intentionally set.

More than 50 firefighters responded to the five-alarm fire on Barrows Street, according to Norton Fire Chief Shawn Simmons.

“Someone knows whether the fire was intentionally set or accidentally set by people who were not authorized to be inside,” Simmons said in a statement.

The Arson Watch Reward Program is offering up to $5,000 for information that helps determine the cause, regardless of if it was intentional or not.

Anyone who believes they have information that will help the investigation is asked to call the Arson Hotline at 1-800-682-9229 or the Norton Police Department at (508) 285-3327.