$200k reward for missing SA mum's remains

The 23-year-old mother-of-two was reported missing by her husband and sister-in-law on August 10 last year, two days after she was last seen, police said on Monday.

A reward of $200,000 was announced for any information leading to the recovery of Ms Ebert's remains, after her husband, Michael Burdon, 41, fatally shot himself at the couple's Manna Hill property on August 16.

Mr Burdon remains the only person of interest in relation to her suspected murder, but investigators believe there are people in the community who know exactly what happened to Ms Ebert, as they seek to find answers for her family in Germany and her two sons.

"We suspect Michael has committed the murder of his wife. We don't believe anyone else was involved in that," Detective Inspector Billy Thompson told reporters.

"Whether other people chose to assist Michael after the murder is a question we need answers to."

Inspector Thompson said the investigation and the length of time between when Tanja was last seen and when she was reported missing gave them reason to believe Mr Burdon would have been involved, or in contact with other people.

"Michael was from a close family. He would have had people within the family that he would have spoken to. We have spoken to lots of those people and they have not disclosed any of those potential conversations that Michael may have had after Tanja died. They need to think about that. They need to come forward."

He said the matter was deeply distressing for Ms Ebert's family in Germany and would "obviously be terrible as these kids grow up not knowing what happened to their mum and not having any answers".

He warned that anyone withholding information "potentially" could face charges, but the focus currently was on finding Ms Ebert's remains and providing answers for her family and children.

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Australian Associated Press