Police investigating the deaths of a prospecting couple hope a fresh search of an abandoned mineshaft will provide their loved ones with long-awaited answers.
Raymond Kehlet, 47, and Jennie Kehlet, 49, disappeared from a prospecting trip to Sandstone, about 660km north of Perth, in March 2015.
Mr Kehlet's body was discovered at the mineshaft weeks later, almost 2km from their camp site, but his wife's remains have never been found.
A coroner in 2021 made an open finding in regards to Ms Kehlet's death, saying it was impossible to determine how she died.
West Australian police confirmed special crime detectives were re-examining the scene where Mr Kehlet's body was found.
It comes after an item of clothing was recently found at the base of the mineshaft by a member of the public engaged by the Kehlet family.
Police Commissioner Col Blanch said it was yet to be determined whether the garment was related to the crime.
"We want to get answers," he told ABC radio on Wednesday.
"We're up there at the moment and we want to go back down that mineshaft and do a very comprehensive search, even after all these years, and see if we can find anything else that can lead us to solve that crime."
Police have engaged the mining industry to assist the "delicate and potentially dangerous" search down the century-old mineshaft, which is described as 12 metres deep and highly unstable.
A combined $2 million reward remains on offer for anyone with information on the couple's deaths.
Coroner Ros Fogliani found Mr Kehlet - who had injuries to his face, neck and right hand - had been violently killed, but it was possible his wife had escaped immediate danger before becoming disoriented and lost.
The couple's friend and colleague Graham Milne - the last known person to see the couple alive - was a suspect but has never faced charges and has denied any involvement.
Mr Milne was granted immunity so his evidence at the inquest cannot be used against him in any future criminal proceedings.
He testified the last time he saw the couple they were chasing after their dog, Ella, on March 21.
Mr Milne said he spent 18 hours prospecting alone, then returned to the campsite in the early hours of March 22 and drove home.
Ms Fogliani said a referral would be made to the director of public prosecutions but it did not reflect any belief she had formed "concerning any action, or omission, on the part of Mr Milne in relation to Ray or Jennie".