The fire was reported just after 7 p.m. at the home on the 11500 block of West Riverside Drive, authorities said.
More than three dozen firefighters responded, extinguishing the flames in 11 minutes.
When they got a closer look inside, they discovered the burned body of a woman.
"The responding Los Angeles Police Department units examined the scene and determined that the death was of a suspicious nature," Lt. Alan Hamilton said.
The cornoner's office will now try to determine how and when she was killed. The cause of the fire is also under investigation.
No arrests have been made in the case, but investigators said someone saw a man with a hat running from the scene.