Firefighters spotted the body while using an aerial ladder truck as part of their investigation into the fire, which was reported at about 2 a.m. in the garage of a two-story home in the 700 block of North White Road, San Jose fire Capt. Scott Kouns said.
They saw the body while knocking off debris on the badly damaged roof of the home, Kouns said.
Firefighters arrived at the home after the initial call to find it engulfed in flames. They located one resident, who was taken to a hospital, but a second person believed to have been in the house had not been accounted for, Kouns said.
He said family members have been notified of the discovery of the body, but that because of the unstable condition of the structure, it will be a long time before authorities are able to get inside the house for further investigation.
The blaze, which was contained at about 4 a.m., caused a majority of the roof to collapse, Kouns said.
"The house is pretty much a total loss," he said.
Because of the structure's instability and the possibility of heavy roof tiles falling into the home, firefighters are making sure it is safe before they enter the home.
A structural engineer is headed out to the scene to analyze the situation.
The investigation into the fire "will be an all-day event," Kouns said.