FRANKLIN, N.H. (AP) – A rat chewing wires while building a nest is being blamed for an apartment building fire.

One elderly man had to be assisted out of his apartment as firefighters worked to put out a fire Saturday that started in the basement of multiunit senior apartment house. Five other residents were able to leave the building unassisted.

Fire Capt. Gary Hicks said the fire started in the basement and traveled through a void space between outer and inner walls of building to the second floor and parts of the mansard roof.

He said the fire was started by arcing electrical wires, a condition caused by a rat.

Capt. Kevin LaChapelle said it appeared the rat had chewed through the wire’s insulation coating.

“It was trying to build a nest,” LaChapelle said.

Hicks estimated that the building received at least $20,000 in damage.