Because fire investigators were unable to rule out arson as a cause Monday, Waterville's fire chief said the cause of that fire remained under investigation.
According to Esler, firefighters were called to 21 Elm St. for a report of a fire shortly after 6:30 p.m. on Sunday.
"There was originally some reports of people trapped inside the building. After deploying a hand line and performing a search of the first and second floor, there was found to be no occupants inside the building," Esler said Monday.
Esler said the American Red Cross is helping the tenants find temporary shelter.
The state fire marshal's office and the Waterville Police Department are working together to determine the origin and cause of the fire.