A suspect in the deaths of a prospecting couple in remote Western Australia has told an inquest the last time he saw them they were chasing after their dog.
The WA Coroner's Court is probing the death of Raymond Kehlet, 47, who was found down a mineshaft 1.8km from his Sandstone campsite, and the suspected death of his wife Jennie, 49, in March 2015.
The couple's friend and colleague Graham Milne, who the court previously heard was a suspect in their deaths but never charged, has been forced to testify despite concerns he could incriminate himself.
Coroner Ros Fogliani has offered Mr Milne immunity so his evidence at the inquest cannot be used against him in any criminal proceedings unless he commits perjury.
Mr Milne testified the last time he saw Mr Kehlet he was on a quad bike chasing after his dog Ella on March 21.
"I told him that they could go and chase the dog," he told the court on Thursday.
"I didn't come here to chase a dog. I wanted to go prospecting."
Asked whether he had been terse, Mr Milne replied: "It may have been a little bit abrupt."
Mr Milne said he also gave Ms Kehlet instructions on how to use the quad bike.
He said the couple were devoted to Ella, who had run off a few times during their trip.
Mr Milne also said Mr Kehlet carried a gun on his quad bike.
"It was his choice, I never queried it at all," he said.
Mr Milne spent the next 18 hours prospecting alone, not too far from the campsite, taking just two sandwiches and 2.5L of water with him.
He later returned to the campsite in the early hours of March 22, packed his things, then went home.
Mr Milne assumed the couple were asleep at the time but did not see them, he said.