CASTRO VALLEY (CBS SF) — Investigators are considering the death of a woman and a one-alarm house fire in unincorporated Castro Valley early this morning as a homicide and arson, according to an Alameda County sheriff’s spokesman.

A firefighter was also injured in the fire, which was reported in the 1800 block of Grove Way at about 2:45 a.m.

“During the autopsy it was discovered that this was likely a homicide,” sheriff’s Sgt. J.D. Nelson said.

The 59-year-old woman, whose name has not yet been released, was found dead in the home’s garage and the fire appears to have started in the one-story home’s attic, Alameda County fire officials said earlier Tuesday.

No one else was at the home when firefighters arrived, fire officials said.