Mystery surrounds the tragic deaths of two sisters whose bodies were found inside a southwest Sydney unit.
Police believe the deaths of the women, aged 23 and 24, are suspicious but have not yet determined the cause.
Police were called following reports a body had been discovered inside the Canterbury unit on Tuesday by "another government agency".
Detective Inspector Claudia Allcroft, from Burwood Police Area Command, said the bodies were in separate bedrooms and had been there "for some time".
"I can't tell you how long. That will be a question for the coroner," she told reporters on Wednesday.
"We will know more once the post mortem examination is completed tomorrow.
"It's a very tragic scene when we go to any deceased persons, let alone two sisters who are deceased and unfortunately, at this stage, we don't know why."
Homicide Squad detectives and forensic police combed the apartment building and were canvassing the street on Wednesday.
Emergency services were reportedly called after neighbours noticed mail addressed to the flat had been piling up.
