CASTRO VALLEY -- A woman's body was discovered in a Castro Valley home that was damaged by a suspicious blaze early Thursday, authorities said.

Alameda County Fire Department crews were called at 12:15 a.m. to the home at 2431 San Carlos Ave., near John Drive, and saw heavy smoke coming from the eaves of the roof, fire department spokeswoman Aisha Knowles said.

Fire crews had the one-alarm fire at the single-family residence under control within 20 minutes and found the body inside while fighting the blaze.

Fire officials have not released the woman's identity, a cause of death or where the body was found in the home.

The Alameda County Sheriff's Office is leading the investigation, though the fire department will assist in finding the cause of the fire. A preliminary investigation reveals an accelerant may have started the blaze, said sheriff's office Sgt. J.D. Nelson.

Sheriff's investigators obtained a warrant after the fire and searched the home, Nelson said. An autopsy could be performed as early as Friday.

No one else was in the home, and no injuries were reported, said battalion Chief Chip Anderson, who worked the fire.

"We believe it was a retired firefighter's home, but we don't know who the person was," Anderson said.

Staff writers Daniel M. Jimenez and Erin Ivie contributed to this report. Contact Natalie Neysa Alund at 510-293-2469. Follow her at Twitter.com/nataliealund.