SANFORD, Maine (NEWS CENTER) -- The massive fire that raged through a vacant textile mill in Sanford is being investigated as a case of arson caused by three boys.
That determination by the State Fire Marshal's Office led to the boys' arrests on Sunday. Their names have not been released, but investigators put their ages at 12 years old for one of the boys and 13 years old for the other two.
The boys are being held at Long Creek Youth Development Center in South Portland. Paperwork on their cases is in the process of being filed with Sanford District Court, clearing the way for their first court appearances.
The fire broke out on Friday night in a rear building at the Stenton Trust Mill complex on River Street. The building is made of brick and concrete and stands five stories tall. Crews from about 20 departments worked for days to keep the fire contained and prevent it from spreading to surrounding properties. As of Monday, it was still smoldering.
PHOTOS: Flames tear through abandoned mill in Sanford
For several days, investigators were unsure of the whereabouts of two homeless men who were known to be staying at the mill. They were finally found safe in Portland on Monday according to the State Fire Marshal's Office.
Work to collect evidence at the mill is being shared by the State Fire Marshal's Office, the Bureau of Alcohol, Tobacco and Firearms, Maine State Police, Sanford Police and the Sanford Fire Department. A press conference providing updated information on their findings will take place at 1 p.m. on Monday.