It began in a mattress in a bedroom.
The investigation continues into the cause of a fire in a home on Tuesday morning.
Officials say 35 fire fighters were dispatched at 2:52 AM to 612 Monarch Ridge Road in Frederick for a mattress on fire. They found the fire had spread to the entire bedroom, and the attic of the two-story, single family home.
Personnel spent 20-minutes bringing the flames under control. No one was hurt.
Damage is estimated at $125,000 to both the structure and the contents.
Investigators say the fire started in the bedroom, where a woman was unable to get out of the bed. Her husband rescued her.
Two people are displaced by the fire and are being assisted by the Red Cross.