The New South Wales coroner has recommended the mysterious death of Jackson Stacker near Byron Bay be investigated by the homicide squad, with Teresa O’Sullivan finding “some aspects of the early [police] investigation raised concerns”.

Stacker had been travelling from Melbourne to Queensland in his Toyota Hiace van in 2021 when the borders closed due to Covid.

The 25-year-old found himself stuck in the northern rivers region. Stacker had been, his father, Ian, told the Guardian, “seeking an alternative lifestyle – he wanted to find a way to live off the land and not impact the environment”.

Instead, the young man found himself in a world of homelessness, drugs and desperation in Byron Bay.

On 23 August 2021, Ian Stacker received a call asking if Jackson’s van was for sale. It had been found abandoned at a rest stop in Sleepy Hollow near Pottsville, about 40km north of Byron. The keys were in the ignition, and the ransacked van smelled of rotting food. Ian’s number was on the registration papers.

Two days later, police found Stacker’s remains under a tree in a nearby paddock. Exposed to the elements for about a month, the remains were skeletal and scattered. His scalp and dreadlocks were 14 metres from the body.

O’Sullivan, the state coroner, recommended on Thursday “that the death of Jackson Stacker be referred to the NSW homicide squad unsolved homicide team for assessment in accordance with their standard operating procedures”.

The magistrate said “a large hunting-style knife” had been found in the 25-year-old’s left chest area.

“The handle of the knife appeared to have been resting on the skeletal remains of his right hand, which was under his body.”

Stacker’s mother, Sandra MacFarlane, visited the scene after her son’s remains were discovered. She found one of his teeth under a leaf.

Forensic pathologist Dr Leah Clifton, who performed the autopsy, concluded the cause of death was “unascertained”.

Clifton gave evidence during the inquest that it was “most likely that Jackson died from injuries inflicted by the knife, but she could not be conclusive as to the cause of his death due to the advanced level of decomposition”, the coroner said on Thursday.

O’Sullivan said Stacker’s family argued the evidence didn’t suggest that by 23 July 2021 – the day after he was last seen alive – the 25-year-old was sufficiently distressed to take his own life.

There was evidence from those who knew him that he was a regular consumer of cannabis. A week before he went missing, he had been badly affected by LSD at a doof in Casino, “upset and crying uncontrollably”, the coroner said in her inquest findings.

O’Sullivan found it was “probable that Jackson was distressed or depressed in the days leading up to his death”, but it could not “be positively established that Jackson took his own life, particularly in the absence of any note or express indication that Jackson was considering self-harm”.

No DNA evidence was extracted from the knife, and there was no evidence that Stacker owned a hunting knife. There was, however, an absence of defence wounds, and “the two chest wounds tend against murder because it is unlikely that Jackson would have stood still while being attacked”, O’Sullivan told the court.

Stacker was “a well-liked person with no real history of aggression or getting into fights”, the coroner said.

She concluded that, on the available evidence, “I would be unable to make findings in relation to the cause and manner of death to the requisite standard”.

Stacker’s family believe the initial police investigation was slow due to a premature assumption that Jackson had killed himself.

O’Sullivan stated that in the absence of being unable to hear from a “detective A” at the inquest, she was “not able to make a positive finding that the investigation … was flawed”.

“I find that some aspects of the early investigation raised concerns, but there is insufficient evidence to conclude that the early investigation was inadequate,” she said.

But O’Sullivan added: “This was a matter where it would have been appropriate to refer it to the homicide squad, at least for initial assistance.”

There was also “an insufficient explanation as to why there was a delay in establishing a strike force”.

It was clear that Stacker “meant a lot to many people and his passing came as a great shock and was felt deeply by those who knew him – none more so than his parents”.

The Stacker family on Thursday said the findings confirmed “what we have said from the very beginning – that there are serious unanswered questions surrounding our son’s death that have never been fully resolved”.

Stacker’s mother said that, over the past two years, further information and additional witnesses had come to light that were not explored in the original coronial proceedings.

“These matters, along with the broader circumstances of our son’s death, warrant thorough and independent investigation,” MacFarlane said on Thursday.

“As a mother, there is a deep and enduring understanding of a child that cannot be easily set aside. We have always believed that the circumstances of our son’s death required closer scrutiny, and today’s findings reinforce that position.”