Authorities are investigating a fire in downtown Platteville that police said may have been caused by “illegal drug manufacturing” early Monday.

The fire at 42 W. Main St. was reported around 4 a.m. Platteville firefighters were on scene, fighting the fire or guarding the site, for 12 hours on Monday.

Firefighters spent considerable time in apartments in the back of the building finding the source of smoke that continued six hours after the fire was reported. 

No one was injured. Main Street was closed in front of the building until mid-afternoon Monday.

The American Red Cross said in a news release that it is assisting “several adults and three children” who lived in one of the building’s apartments.

The state Department of Justice Division of Criminal Investigation fire marshal was at the scene Monday afternoon.

For more on this story, read The Platteville Journal this week.