Firefighters responded shortly after 10:30 a.m. to a house in the 2300 block of West Manly Avenue, where flames spread to the attic. Firefighters contained the blaze to the second floor of the structure, a spokesperson for the Orange County Fire Authority said.
The identities of the deceased were not immediately disclosed. Police said the bodies were burned beyond recognition, but one body was believed to be that of a male.
Homicide detectives were en route to the scene "because of the suspicious circumstances behind the fire," said Cpl. Anthony Bertagna of the Santa Ana Police Department.
Arson investigators were working to determine the cause of the fire.
MORE: Neighbor just told me police were at the home last week, appeared to take a man into custody. https://t.co/5BVaJ457HY— Greg Lee (@abc7greg) January 1, 2019
The family of the woman who owns the home said they're heartbroken as they wait for confirmation of their belief that she was killed.
Officers were at the same home Saturday, arresting Ahmad Allasad on suspicion of domestic violence against his wife.
"That guy, he's no good. I told her let him move out, but she don't' listen, so I just find out he hit her many times," shared one neighbor who identified herself as Sue.
Friends and family said the wife's name is Thuy Nguyen. They said she owns the house and rented to Allasad before they got married.
Her brother, Scott, didn't want to show his face on camera but said Allasad threatened them before he was arrested and bailed out. He said he believes his sister and Allasad are dead.
"If we call the cops, he's going to come back and kill everyone and burn down the house," Scott shared.
Police were waiting for the coroner to identify the bodies and determine exactly what happened.
"Circumstances of the call on the 29th lead us to believe that they may be the same two individuals," Bertagna said.
Two cats also died in the fire, but firefighters managed to save a dog in the home.
Police said a woman who rents a room in the house was able to escape the blaze, while two other renters were not home at the time.
Two officers suffered smoke inhalation but were expected to be OK.