On Friday at approximately 3:45 a.m., San Bernardino County Fire Department responded to a residential structure fire in the 16600 block of Boyle Ave. When arriving on scene, firefighters located a single story family residence with smoke showing from the roof and flames in the rear of the structure. The fire was contained in about 30 minutes. At this time, the cause of the fire is unknown. Fontana PD is handling the investigation.