Burnt and fragmented human remains discovered in rock pools in Melbourne's east in 2018 were likely placed in the ocean only a short time before they were recovered by Parks Victoria staff, a coroner has concluded.
But despite extensive forensic analysis and searches in Australia and overseas, the identity of who they belonged to is still a mystery nearly six years on.
The first fragments were discovered on January 11, 2018 by two Parks Victoria officers patrolling the Ricketts Point Marine Sanctuary at Beaumaris.
Police were called and recovered more bone fragments on that day and again on January 18.
In total, 426 bone fragments were found scattered across an area of about eight square metres
Testing determined the bones, which included fragments of skull, chest, arms, legs and vertebrae were human remains, and belonged to the same individual.
No clothing, personal effects or other items were found in the area, leaving authorities few leads.
The remains were examined by forensic anthropologists Samantha Rowbotham and Soren Blau, who were able to provide a biological profile of the individual, but cautioned the poor preservation of the remains mean it was only an estimate.
They believe the bones belonged to a Caucasian woman, older than 20 who stood between 151 and 160cm tall.
No time of death could be given, but Dr Rowbotham concluded that the previously burnt remains were likely placed in the ocean a relatively short time before they were recovered.
Had they been in the water for a substantial time they would have washed away or further disintegrated, she believed.
Odontologist Lyndall Smythe analysed dental remains but was unable to match to any records to establish an identity.
Six bones fragments were sent to a private DNA testing company in the United Kingdom for mitochondrial DNA testing, after Victorian forensic specialists concluded there were no further viable options in Australia.
But because the bones were in relatively poor condition they were found to be poor candidates for such analysis.
Victorian Coroner Kate Despot on Wednesday concluded that despite exhaustive investigations it was not possible to make findings about the identity, cause or circumstances surrounding death.
She said the investigation could be re-opened if further facts and circumstances were revealed later.