A fire that caused heavy damage to a home in Sanford on Wednesday afternoon may have been started by a lightning strike.

Capt. Brian Watkins of the Sanford Fire Department said a husband and wife reported that their home at 163 Whichers Mill Road was struck by lightning around 2 p.m. The couple escaped safely, but when firefighters arrived the fire had already caused extensive damage to the home’s interior.

Though the couple said the fire was caused by lightning, Watkins said the cause remains under investigation.

Watkins said the fire was reported during a thunderstorm that brought heavy rain and winds to Sanford an other parts of southern Maine. The couple are expected to stay with relatives.