Police interviewed Ms Athanassiou's partner Daniel Johnston about the day of Ms Athanassiou's death, but he denied knowing anything about it or being in the area at the time -- despite two witnesses putting him at the scene.
During a second interview with police, he said he couldn't live with not telling the truth.
He said he had left Ms Athanassiou, who was red in the face and wheezy, not far from where her body had been found while he searched for magic mushrooms and returned to find her unconscious.
He left her about 11am and told people nearby there was a woman in need of help.
His excuse for not staying with her was that he did not want to be "busted" for having drugs on him.
In the findings, Coroner Evans said Mr Johnston told the court it was about 9.15am when he left her, but declined to give any specific information on the grounds it would incriminate him.
The first person to get to Ms Athanassiou, after being told about her by Mr Johnston, said her skin was grey and she appeared dead, but Mr Johnston insisted she was still alive.
Mr Johnston then left the scene and asked other nearby people to call for help as he was leaving.
Mr Evans said Ms Athanassiou led a "sad and somewhat lonely life".
"The circumstances of her death leave many questions unanswered."
As a result of Mr Johnston refusing to give a full account of the circumstances around what he was doing between 9am and 11am, the court was unable to form a full picture of events, he said.
"The court has expressed its concern that he should have left his long time partner in a distressed state, sitting alone in a concrete shelter ... while he went off to pick mushrooms."
When he next saw her, Ms Athanassiou was "close to death, if not already dead", Coroner Evans said.
"At the time he left his partner, Mr Johnston knew that members of the public were arranging for emergency help. Ms Athanassiou was left to die alone."
The police file into her death would remain open, Coroner Evans said.
