Someone was living "on and off" in a Melbourne home where a mother of four's body was found rotten in the bathtub earlier this year, police say.

Police believe the remains of Sarah Gatt, 40, had been lying inside her Kensington home for more than eight months before they were discovered by police in January this year.

It is thought she was attacked at the Lambeth Street unit sometime between April 20 and April 24 last year.

Her body was discovered by chance when police smelled a bad odour while visiting the street for an unrelated matter on January 3.

Detective Inspector Tim Day said efforts had been made to hide Ms Gatt's body inside the property and make out that she was still alive.

Police believe whoever killed Ms Gatt tried to make it appear that she was still alive. ( Supplied: Victoria Police )

"There's certain evidence at the crime scene to suggest that attempts were made to conceal the fact that Sarah's body was there in the apartment," he said.

"What those details are I can't go into."

Ms Gatt's family, who had lost contact with her, said her life took a wrong turn when she started taking drugs as a teenager.

But her stepmother Cheryl Gatt said she did not deserve to have her life cut short in such circumstances.

"No-one deserves to die like that, no-one," she said.

Police questioned five "persons of interest" in January but have not laid any charges.

Detective Inspector Day said all five were known to Ms Gatt, who had previously had involvement with police.

He said someone was living at the property "on and off" when the body was found, and detectives had a good idea about what had occurred.

"Like all jigsaw puzzles it's now about putting those pieces together and forming the clear picture about what happened," he said.

Police want to hear from anyone who saw people coming and going from the house. ( ABC News: James Hancock )

None of Ms Gatt's four children were living with her when she died.

Police are seeking witnesses who saw anyone coming or going from the property since Ms Gatt's death.

They also want to hear from anyone who was told Ms Gatt was still alive after April 20.

Cheryl Gatt urged anyone with information to phone police.

"Even if you just think 'oh it's not that important,' please come forward, she deserves that."