Missing Brisbane woman Lesley Trotter's remains are unlikely to ever be found despite an extensive search of the tip where her body is believed to have been dumped, police have admitted.
The 78-year-old's body was left in a wheelie bin on the footpath outside her Maryvale Street home in Toowong on March 28.
The bin with her body in it was collected by a rubbish truck early that morning and emptied at a dump at Swanbank, west of Brisbane, according to police.
Three weeks after she was reported missing, the search at Swanbank Renewable Energy and Waste Management Facility began.
Police and army personnel were tasked with sifting through nearly 1,000 tonnes of waste in a three-week aerial and ground search of Swanbank.
But the search for Ms Trotter was suspended on May 11.
Brisbane Region Crime Coordinator Detective Superintendent Andrew Massingham told the ABC the search of the rubbish tip had stopped because waste was decomposing at a rate faster than predicted.
"It went from well-defined items to a layer of black sludge," he said.
"This made the chance of identifying anything extremely difficult, and items had been spread in an area far greater than we initially thought."
The forensic value of any items which could have been recovered by the fourth week of the search would have been low, and it is unlikely Ms Trotter's body would ever be found, Detective Superintendent Massingham said.
The investigation into her death is ongoing.
Ms Trotter's death is believed to be suspicious but police are not ruling out another cause, including a medical episode or "subsequent misadventure".
The retired schoolteacher last contacted her family on March 27 but it was not until April 11 that police said they believed she was dead.
More than 40 detectives were originally tasked to the case and several crime scenes were established around Toowong.
Detective Superintendent Massingham had previously said Ms Trotter's habit of sorting rubbish "could be linked to her death".
Detectives are now probing several motives for her death, after investigations revealed Ms Trotter had a number of disagreements with people who lived nearby her unit.
Police have urged anyone with information, particularly video footage from between 5am and 7am on March 28 near Ms Trotter's unit, to contact police.
