The grim search of an outback pastoral property has failed to find any sign of missing and believed murdered mother-of-two Tanja Ebert.
Police converged on the Mannahill property in South Australia's northeast on Friday, using officers on horseback as well as earth moving equipment to scour areas of interest across the property's 410 square kilometres.
State Emergency Service volunteers were also involved, conducting a line search through the scrub.
Nothing was found but a police spokesman said efforts to locate Ms Ebert and other investigations related to her disappearance would continue.
"It's a massive task. Well do our best to find her but there's no guarantees," Superintendent Des Bray told reporters ahead of the search.
"There's a vast area to search. But if we put in the effort and have a bit of luck we have a chance of finding her."
Police said Ms Ebert's husband Michael Burdon, 41, made no admissions and offered no clues as to the whereabouts of his wife before he took his own life at the property on Wednesday.
He remains the only suspect in the likely murder of the 23-year-old.
But Mr Burdon was not under arrest at the time and there was still no evidence to prove he had killed his wife of about six months, Supt Bray said.
Ms Ebert was last seen near Roseworthy, more than 50km north of Adelaide, as she drove home from Adelaide with her husband and children last week.
Mr Burdon told police she became agitated and got out of the car and walked off.
However, he did not report her missing, with another family member contacting authorities two days later.
Ms Ebert came to Australia from Germany several years ago and married her husband in February.
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