After dozens of volunteers and officers scoured a remote sheep station without success, police have scaled back the search for missing mother Tanja Ebert.
It's believed the 23-year-old woman may have been murdered by her husband Michael Burdon, who shot himself dead on Thursday as police questioned him over his wife's disappearance.
But on Friday police could find no trace of her, even after using Mr Burdon's own machinery to excavate a section of land just metres from their homestead, believing she may have been buried there.
It's now feared her body may never be found - if it is on the vast property at all.
The last remaining detectives left the property on Friday evening.
A steady stream of search crews have headed back to Mannahill after all the key areas of search interest were ruled out.
"There was very significant excavation done adjacent to a creek next to the homestead where recent earthworks have been undertaken, but sadly that didn't reveal anything," detective superintendent Des Bray said.
"It's been an extensive search, it's very frustrating - we've been working very hard to get a result for Tanja's parents."
They have been offered financial assistance to fly out from Germany - to undertake a heartbreaking journey knowing they may never be able to say goodbye.
While Michael Burdon took his secret to the grave, police are urging anyone else with information or knowledge of what happened to Ms Ebert to speak up.
"It's actually quite rare for people to commit a murder and not tell somebody," detective superintendent Bray said.
"They won't be in trouble if they haven't told us up until now, but they should think of Tanja's parents and come forward."
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While police have scaled back their search, the investigation is far from over.
Major Crime detectives will return to Adelaide and assess the information gathered so far.
They will also continue to interview the couple's family and friends, refusing to give up hope of a breakthrough.