Police found the body of Sarah Gatt, 40, after being called to her home in Kensington, just north of the CBD, on January 3 this year.

They were there on an unrelated matter, but could smell her before they entered the Lambeth Street commission housing unit.

Inside, they found the mother-of-four in the bathtub. Today, more than two months after the discovery, police revealed a “disturbing” twist.

They say Ms Gatt, who was a known drug user, died as many as eight months before she was found and that people who knew she was dead pretended she was alive and well.

“There are certain things I need to keep to myself, but I can say and reaffirm that police believe that both the death itself was covered up and that there was an implication that she was still alive after April 20 last year,” Homicide Squad Detective Inspector Tim Day said on Tuesday.

He said “certain actions by certain people” had led police to believe Ms Gatt was being “kept alive” for eight months after her death.

The former teen model’s body was found hidden inside the apartment, police said, but they would not reveal exact details.

Insp Day said she was found “in the bathtub but certain attempts were made to conceal the fact that Sarah’s body was in the apartment”.

When asked if anybody else was living in the home at the time her body was discovered, Det Insp Day said “on and off”.

Police arrested three men and two women shortly after January 3. They say all were questioned by police but none were charged. All five were released pending further inquiries.

Insp Day say there are people out there who “know what happened and we are urging them to come forward”. It’s a message shared by Ms Gatt’s grieving family who told reporters they hadn’t spoken with their daughter in 18 months.

“She was a great person. I couldn’t fault her at all, she was great. Then she went down the wrong path,” Ms Gatt’s father said.

“I tried (to bring her back) and she didn’t want to do it. I lost contact with her about 18 months ago because she didn’t want to see me. Whatever I said, she just didn’t want to do it.”

Ms Gatt’s mother said her daughter had four children “aged seven to 18” but “kept everything to herself”. She said she started using drugs as a teenager and her life spiralled from there.

“She had a lot of big dreams which, to be honest, I knew would never really happen but she had good intentions,” she said.

“No one deserves to die like that. It doesn’t matter what happened, she doesn’t deserve to die like that.”

Det Insp Day would not be drawn on whether multiple people were involved in her death or whether somebody “was pretending to be Sarah”. He said a number of “stories” about Ms Gatt had been circulated after April 20 when police believe she was killed.

Asked whether he thought police had reached a dead end, he said “far from it”.

“We’re very optimistic in terms of the investigation. Police have a pretty good idea of what they believe has occurred.”

Anyone with information is urged to call Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au.

Email: rohan.smith1@news.com.au | Twitter: @ro_smith