The fire began in one unit of a four-unit single story apartment house in the 3700 block of Norwood Avenue. The police department was called in about 10 a.m. after firefighters worked to extinguish the blaze.
Neighbor Eric Kelley said he tried unsuccessfully to enter the burning building and rescue the victim locked inside.
"He was hollering for help," Kelly said.
Officers are treating the death as a homicide due to suspicious circumstances that include trauma to the body.
The victim was a man in his 30s, police said.
"We don't know if the fire caused the homicide of if it was trying to cover up what actually happened," officer Andrew Pettit said.
The unit where the victim's body was found was destroyed, while the three adjacent unites are not inhabitable, Pettit said.
One tenant lived in the burned apartment, while seven people occupy the three other units, apartment manager Kimo Morreira said.
No other people were injured, but two dogs in the burned apartment also died of smoke inhalation, Pettit said.
A vehicle, an older model white Honda Civic with no hubcaps, was seen leaving the area. The driver, a man in his 20s, may have some connection to the fire, police said.
Police said Norwood Avenue between Grand and Morey avenues would be closed for several hours.
PHOTO CAPTION: Police and fire crews respond to a fire at 3700 Norwood where a male in his mid-30s was found dead. Jose Luis Villegas/Sacramento Bee