WATERVILLE — Investigators say an electrical problem is responsible for a fire Wednesday that displaced eight people from two apartments on Spruce Street

Sgt. Ken Grimes of the State Fire Marshal’s Office said investigators closed the case Thursday. The fire was deemed accidental, but the exact cause is unknown.

“The fire originated in the attic near several electrical conductors. Something went wrong with the electrical system itself,” he said.

Beginning about 5 p.m. Wednesday, about 30 firefighters from Waterville and Winslow fought the blaze at 38 Spruce St., on the corner of Drummond Avenue. By 6:40 p.m., the fire was under control, but the roof had partially collapsed.

The Red Cross has provided temporary housing to the building’s tenants, who were all related.

George Jurdak, the building’s manager, said it’s too early to say whether the two-story structure will be repaired or destroyed.

“We’re still assessing the situation,” Jurdak said Thursday.