When firefighters arrived the house was fully engulfed in flames. It took crews 13 minutes to get the fire under control.
The bulk of the fire was confined to a room in the 800-foot guest house, where firefighters found the deceased teenager, identified as 16-year-old Edward "Eddie" Miller, and three dogs. The fire moved very quickly through the wooden structure.
Fire Battalion Chief John Duca says there were no smoke detectors in the home.
"Little doubt in my mind that if you had smoke detectors, at least your dogs are going to wake up with that noise. If you don't, they will," said Duca. "And that wasn't the case in this situation. It's very unfortunate."
It is unclear if the teen was sleeping or if he was overcome by flumes.
Authorities say he was living in the guest house with his mother, who was apparently not home at the time of the fire.
The cause of the fire is under investigation. Arson investigators and homicide detectives are on scene to help assist in the investigation.
Neighbors mourn the death of the teenager.
"I really miss him because he looked like my son and daughter," said neighbor Dilruba Khan
The victim was a special needs student who was in 10th grade at Reseda High School.
Counselors are at the school to help students cope with the loss.