The State Fire Marshal’s Office says the cause of Friday’s fire that destroyed McCormack Building Supply in Winslow will remain undetermined.

According to Maine Department of Public Safety Spokesman Steve McCausland, investigators said the fire started near a building in the back of the complex, known as the pine shed, where white pine lumber was stored. It is believed the monetary loss of the fire would exceed $4 million, McCausland said.

Investigators said they could not rule in or out any one source for the fire because of the extensive damage, McCausland said.

According to McCausland, investigators interviewed about 25 people who were in or near the buildings when the fire broke out about noon on Friday.  Those interviewed included employees, customers, and employees of a paving company which was paving on the property.