A man arrested over the fatal stabbing of a French tourist in the Northern Territory outback is yet to be interviewed or charged amid growing indications he has mental health issues.
Pande Veleski was taken into custody on Thursday after the death of the 33-year-old Frenchman the previous afternoon and remains in the Alice Springs hospital where he is being treated for heat exhaustion and dehydration.
The victim was stabbed in the neck in an unprovoked attack in front of his wife at a roadside rest stop at Aileron, north of Alice Springs.
Detective Superintendent Travis Wurst said the ongoing investigation of the "random and obscure" killing was trying to find a motive.
"We'll endeavour to interview and lay a charge in due course," he said.
Supt Wurst said commenting on the man's mental health or any possible fitness to plea would be "jumping the gun".
But posts on Veleski's Facebook page indicated he had suffered mental health issues for some time.
"Here is a man who has suffered long-term mental illness, as I know the family," one person said.
"I can assure people that his poor parents and family are totally distressed about the victim, as well as their own son, who has suffered for many years in a barely adequate mental health system."
Veleski's brother Tony also confirmed the 35-year-old had previously been treated for a mental health condition.
"We're really sorry for the French tourist, and we're sorry for my brother as well." Tony told the Sydney Morning Herald.
Tony said the family did not know he had left the state and thought his brother had travelled to the family's holiday house in Dromana, on Victoria's Mornington Peninsula.
"We were meant to go there today to see him, to spend time with him, me and my son," Tony said.
After the stabbing, Veleski fled the scene in a grey Hyundai which was soon stopped by police at Ti Tree.
It's alleged he then fled into the bush on foot, but was found naked the next morning, while a search of the area uncovered items of clothing believed to be his.
The victim of the attack and his 30-year-old wife had only recently arrived in Australia.
As her husband lay dying she flagged down another couple in a passing car with a nurse staying at the scene while her husband drove 30km to the nearest telephone at the Aileron Roadhouse to call police.
The victim's wife was discharged from hospital after being treated for shock and is also yet to be interviewed.
"She is extremely upset and traumatised by the events that she witnessed," Supt Wurst said.
"We have offered her as much support as we possibly can.
"But we are not rushing to speak to her and obtain a statement from her."
Detectives have called for any motorists in the area at the time of the attack to make contact, particularly if they have dash-camera footage.
They also want to hear from anyone who may have seen the suspect's Hyundai i20 or the car being driven by the French couple's Red Toyota Rav4 with South Australian number plates.
