After 24 years on the run, New Zealand murder accused Grant David Mitchell walked into Atherton police station west of Cairns, in northern Queensland, and gave himself up.

But for a rogue kangaroo on the road between Mareeba and Mutchilba, west of Cairns last October, Mitchell might still have been using the orchards in the area as a safe haven to live and work, far from the prying eyes of NSW police.

Mitchell, who was riding a motorised bicycle, suffered severe head injuries in the collision with the animal, starting a chain of events that would lead to his surrendering to authorities on January 9.

Mitchell was the main suspect in the death by strangulation of his girlfriend, fellow New Zealander Nella Celeste Poli, a 19-year-old barmaid, in Sydney in May 1987.

Ms Poli's mother discovered her daughter's body after she failed to turn up for work.

Mitchell is due to reappear in the courts in Sydney accused of murder.

Media reports after Mitchell gave himself up incorrectly said he had been living as a recluse in the remote settlement of Irvinebank, that he would hide under the floor of his tumble-down cottage when anyone came near and that he would mutter darkly about having killed someone in a past life.

The man named in those reports is apparently a little miffed at being accused of being implicated in a murder.

Meanwhile Mitchell, 61, was living an almost normal existence 100km away on farms in Mutchilba, using the alias of Peter John Bowers.

The owner of a fruit farm where Mitchell worked for 11 years,after spending eight years on another nearby, said he believed that he had "simply had enough".

Raymond, who did not want his surname disclosed, said he believed Mitchell's accident had been the catalyst for him turning himself in.

Mitchell spent a couple of years in the Penrith area of Sydney after the killing, working for a building firm.

But when the tax department introduced tax file numbers, meaning he needed an ID, he moved north for the cash-in-hand work of the orchards and fruit farms of Queensland.

Though vague about his past, Mitchell made friends in the area and even took part in community events.

But he always avoided contact with officialdom - no Medicare identification (Australia's public health system), no driving licence. His motorised bicycle did not need a driving permit.

Things were going fine until his collision with the kangaroo which put him in Cairns Base Hospital for 10 days with serious head injuries.

But worse, because he was not in the system he had no Medicare and was left with an A$11,000 ($15,000) hospital bill he was unable to pay.

After a short time back on the farm, Mitchell suddenly left without saying anything to his friends or to Raymond and his family, apparently fearing questions from authorities about his inability to pay up. He then stayed in squats and in tents in the Atherton area, southwest of Cairns.

Mitchell had been in a short-term relationship with a woman while on the farm, but had difficulty coming to terms with the break-up.

Raymond believed that after his accident, everything simply got too much for Mitchell - his injuries, unable to focus or concentrate, his conscience, anxiety about renewed questions about why he was not in the system, going on the run again and sleeping rough in the wet.

"What is a 61-year-old man going to do running around like a lost dog?

"I think he just wanted to get it over and done with."

* Nella Poli was murdered in Sydney in 1987.

* New Zealander Grant Mitchell was the main suspect but disappeared.

* He walked into a police station in January and gave himself up.

* Mitchell had been living on farms in Mutchilba using an alias.