"Significant suspicions" hang over the death of a five-year-old boy from outback NSW following a head injury, but a coroner says there's not enough strong evidence to refer anyone of interest to authorities.
The boy from Lightning Ridge, who cannot be named for legal reasons, died in a Sydney hospital on March 24, 2010, due to complications from a blunt force injury to the head.
But in her findings delivered on Tuesday, deputy state coroner Harriet Grahame said an inquest was unable to determine whether the child died as the result of an accident or homicide.
It is clear the boy was injured sometime on the night of March 19 or early on March 20, but his family's accounts of what happened in his home that evening were "unreliable" and "conflicting", Ms Grahame said.
The partner of the boy's mother initially told police he had woken up twice during the night to help the child, who had vomited and then had an accident or "pooed himself".
The man said he later heard the boy screaming and went to his room to find he was "having a seizure" in his bunk bed and was concerned he may have fallen out of it.
Ms Grahame said the boy's mother's evidence at the inquest "differed in some respects" to her partner's account, but that may have been due to the time that had passed since then.
The boy was taken to Lightning Ridge Hospital on the morning of March 20. He was transferred to Sydney Children's Hospital in Randwick that afternoon where he later died.
The magistrate noted the partner's "unusual" behaviour - as described by the child's family at the inquest - after the boy was taken to hospital, including cleaning the house and pulling apart bunk beds.
Ms Grahame accepted evidence that the man had a temper which he found difficult to control, and that he beat and kicked the boy's mother on occasions.
But the deputy coroner said while "significant suspicions remain" over the boy's death there was not enough ground to refer anyone to the Director of Public Prosecutions.
She recommended the inquest be re-opened if further evidences comes to light.