Firefighters have put out a two-alarm fire at 158/160 Great Plain Road in Danbury and they are investigating another fire on Whitlock Street.
The Great Plain Road fire was reported at 7:15 a.m.
Officials said the house was vacant when the fire broke out. The owners are from New York and do not live at the house.
Investigators are considering the Whitlock Street fire an arson and that someone poured gasoline in the front door and ignited it.
Seven people were in the house when the fire started.
"Smoke detectors work," Danbury Fire Marshal James Johnson told the Danbury Patch. "They heard the alarms, put out the fire and got out of the house. This is first-degree arson."
The fire was extinguished quickly and the damage is minor, fire officials said.
The fire was reported about two hours before the Great Plain Road fire.