A property on South Australia's Yorke Peninsula has been the subject of a two-day search for Colleen Adams, who has been missing for 45 years.
Ground penetrating radar and specialist camera equipment has been used to forensically examine the Maitland property where Mrs Adams lived with her husband and two daughters.
SA Police Head of Major Crime Des Bray said the search was sparked by an identified anomaly at the former family home.
"We dug out a concrete slab under a garden shed and we are also closely examining a patch in the garden, however at this time we have not located any evidence linked with Mrs Adams' disappearance," he said on Tuesday.
Mrs Adams' husband, Geoff, told police that when he awoke at 7am on November 22, 1973, his wife was fully dressed with two packed suitcases.
He said she told him she was leaving and never wanted to see him or their two young daughters again, before getting into a car with a middle-aged woman he did not know.
Mrs Adams was reported missing by her mother about a month later, and has not made contact with anyone or touched her bank accounts since her disappearance.
Detective Superintendent Bray said police have spoken with a suspect in the matter, and do not believe Mrs Adams is still alive.
"We have followed numerous leads over the years, including a previous search of this property and of a rubbish dump on Port Clinton, but we have found no sign of her," he said.
"Once we have finished at this property, we will have data to examine, and it may be necessary to return to this address again in the future."
A $200,000 reward is available for anyone with information which leads to the recovery of Mrs Adams' body, or the arrest and conviction of the person responsible for her murder.
