By MyFM's Rick Michaels -The State Fire Marshall’s Office is investigating the cause of a fire at a three-story building in the downtown area of Hopkinton yesterday morning. No one was injured. The blaze broke out around 9:30 yesterday morning at 17 Main Street in Hopkinton with heavy flames and smoke showing from the top floor and roof of the structure and quickly became a three-alarm fire with many surrounding communities called in to help put out the flames. The fire destroyed a building that housed two apartments and four businesses and was brought under control in about an hour. Main Street was shut down in both directions for a time as firefighters from Holliston, Framingham, Upton, Ashland, Westboro and Southboro assisted the Hopkinton Fire Department. The Milford Fire department responded with an engine company and later a ladder truck was requested. The blaze is not believed to be suspicious.