Sources told Eyewitness News that police found the woman dead in bed. She had been raped and murdered.
The cause of death will be determined once the autopsy is complete.
The New Jersey State Police arson squad is assisting the police and prosecutor's office in the investigation.
The victim's name has not been released.
Anyone with information is asked to call Detective Michael Machen at the Old Bridge Police Department at (732) 721-5600, or Investigator Paul Miller at the Middlesex County Prosecutor's Office at (732) 745-4466.