The fire started just before 2 a.m. Saturday on Balfour Drive, in the Winburn area.
Witnesses reported hearing an explosion, then seeing big flames and smoke.
By the time firefighters arrived, the house was fully engulfed.
Two young boys inside at the time were able to get out safely.
Investigators are now focusing on the backyard of the house, where an accelerant sniffing dog seemed to notice something suspicious.
But so far, they have not made a ruling on the cause of the fire.
A man was arrested nearby for alcohol intoxication. Investigators say also he's a person of interest in this fire.
The family that lived in the home is now staying with relatives.