Cecilia Faith Miska Devine was last seen getting directions at a hotel in Katoomba in the Blue Mountains on September 6, 2018 before withdrawing $700 from an ATM and making purchases at Coles and Rivers Clothing Store.
Over six months later, the 41-year-old's naked body was found lying face up in shallow water by a Water NSW scientist working at the Upper Cascade Creek dam on March 18, 2019.
After an inquest, coroner Elizabeth Ryan narrowed down the timeframe of Ms Devine's death to between September 6 and 13 but could not determine how the singer had died.
"I find there is insufficient evidence to establish what the cause or manner of Cecilia's death was or to exclude the possibility that she died as a result of misadventure or of homicide," Ms Ryan said on Tuesday to a courtroom filled with Ms Devine's family and friends.
The coroner previously heard that Ms Devine had been diagnosed with bipolar disorder.
When she experienced a mental health episode, she would often throw away her mobile phone and walk long distances without telling people where she was.
However, friends and family were sceptical about claims she voluntarily walked to a remote, unfamiliar location like the dam, saying she normally sought assistance at safe places like hospitals.
During a land search of the catchment area, police only found a single shoe belonging to Ms Devine but did not locate the rest of her clothes or belongings.
An orange towel with the DNA of an unknown male was also found in bushland near the dam.
A mapping business which conducted aerial fly-bys of areas including Katoomba provided police with an image of the Upper Cascades Dam taken on September 13, 2018.
In this photo, an object the shape of a body was seen floating in the water around 65 metres from where Ms Devine's body was found six months later.
An expert in forensic decomposition chemistry gave evidence that it was feasible the 41-year-old's clothing had naturally separated from her body over time while she was in the water.
However, it was not possible to definitively conclude that this is what actually happened, Ms Ryan said.
The deputy state coroner offered her sincere sympathies to those grieving her death.
"They have lost a person whom they loved very much and to their deep sadness is the added distress of not knowing what happened to her," she said.
After she released her findings, the NSW government and police announced the $500,000 reward.
Blue Mountains police commander John Nelson said he hoped the reward would encourage anyone to come forward who may have seen Ms Devine.
"Prior to her disappearance, Cecilia travelled from Newcastle to Katoomba yet we still don't have firm evidence of how she got here, why she made the journey, or how she died," Superintendent Nelson said.
Speaking to AAP after the findings were delivered, Ms Devine's friend Rosie Olk said she was happy with the open findings.
"It gives us the opportunity to search for more answers and for the possibility that somebody who knows something may come forward," she said.
"We're really pleased that Cecilia's been given justice in that way."
But friend Sharn Parker said the open finding left the family no closer to know what actually happened.
"It's a bittersweet day," Ms Olk said.
In remembering her friend, she described Ms Devine as a beautiful person with a really big heart.
"She never would have hurt anybody and we miss her terribly every day," Ms Olk said.
Lifeline 13 11 14
beyondblue 1300 22 4636
31°C