A coroner has directed police to launch a fresh investigation into the death of Gore preschooler Lachlan Jones, describing much of what happened as a "shambles".

Coroner Alexander Ho also shut down "implausible" accusations the three-year-old was killed, frozen and dumped by his mother and half-brothers in 2019, saying she did not harm her child.

Two police investigations concluded Lachlan accidentally drowned in a council oxidation sewage pond a little over a kilometre from his home, although his father Paul Jones disputed the findings.

In delivering his findings to a packed courtroom in Invercargill, coroner Ho found the boy ran down the street to the sewage ponds on the night he died but he could not establish how the boy got into the water or his cause of death.

He directed police to reinvestigate Lachlan's death because of a multitude of unanswered questions, including whether it was "a calamitous confluence of chance".

"It would be remiss to overlook the fact that Lachie was able to come to harm because he was not being adequately supervised, or to overlook how the conduct of the subsequent police and medical investigations into this death have compromised my ability to make findings about how a vulnerable three-year-old child came to die," he said.

"Bluntly, it is difficult to escape the lingering impression that much of what occurred was a shambles which could, and should, have been avoided."

Lachlan Jones' father Paul Jones, family members and friends were in the public gallery to hear the coroner's findings, many of whom wore hoodies emblazoned with #Justice4Lachie, angel wings or large rainbow lollipops.

Coroner Ho said it was "inherently improbable" that Lachlan's mother was complicit in killing her child before she ordered pizza that night, nor any evidence that Lachlan's body was placed in a freezer.

"I accept that a morally moribund mother who accidentally killed her child in a momentary fit of violent exasperation might well panic and try to cover it up, but I do not think a natural reaction would be for her to pick up the phone and order a pizza with extra aioli," he said.

Coroner Ho found police almost immediately formed a view that Lachlan's drowning was accidental and never treated his death as unexplained or suspicious, instead relying on an untested account from his mother and on eyewitness sightings.

He told the court he could not rule out the possibility of foul play as a result of police failings, including confusion over who was in charge and neglecting to seek expert input from criminal investigators.

"There were frankly astonishing scenes at inquest of two senior police officers each disclaiming responsibility for leading the investigation," he said.

Coroner Ho said it was concerning that police had not considered foul play given there was a two-hour window between a sighting near a road corner and when he was found in the pond.

"That is ample time for harm to befall: a push into the pond or a deliberate holding underwater of him would take only seconds," the coroner said.

Investigation flaws

Police acknowledged "missed steps" in their first investigation, triggering a formal review, while a second concluded there was not enough evidence to lay criminal charges.

Coroner Ho identified "shortcomings" in the investigations.

"There was confusion about the identity of the officer in charge in the first investigation. It did not bode well for the quality of the investigation that no one could tell me who was actually in control," he said.

He found some eyewitnesses' statements were not taken promptly, others were recorded as saying things about areas they had no first-had knowledge about, police did not seek expert criminal investigation advice from CIB and the police report for the coroner contained factual errors.

He did not accept the police investigation correctly detailed what happened that night and found many instances where the evidence did not support what the police presented fact.

Coroner Ho directed police to launch a further investigation into Lachlan's death and report back by 16 January 2026, with the findings to be provided to the Independent Police Conduct Authority and the New Zealand Medical Council.

"The fact that I am directing a re-investigation should not be taken as implicating any individual as complicit in or responsible for Lachie's death," he said.

"I emphasise that the reinvestigation I am directing should include not only those incomplete issues which I have identified in these findings but also any other matter which police would normally examine during their usual investigative process. It is to be a full and fresh investigation."

Accident or something sinister?

Coroner Ho had hoped to answer the question of how the boy came to be floating in a sewage pond more than a kilometre from his home late on a hot summer's night.

Lachlan's father Paul Jones and others never accepted that he would run such a long distance in a soiled nappy, barefoot down a gravel road and scale a wooden fence so late in the day.

Instead, they believed others were involved in his death.

During the inquest Jones' lawyer Max Simpkins accused Lachlan's mother and her two older sons of killing the boy and storing his body in a freezer before dumping it to try and cover up his death.

Coroner Ho said there was enough evidence about her movements - including scanning into the depot where she worked - and her conduct - exchanging innocuous text messages with her son about the weather and playful text messages with Jones - that suggested it was unlikely he died during that time.

There was no evidence to support the accusation that his body was ever placed in a freezer, he said.

"Michelle Officer did not cause Lachie direct harm in a manner materially contributory to death after Lachie turned down Grasslands Road," he said.

"It is not otherwise possible to find whether there was third party involvement in Lachie's death."

The early death theory was not plausible because he found that Lachlan was alive and running down Salford Street that night, the coroner said.

He detailed many witness accounts of a small child wearing a high-vis vest and emergency services hat.

"The child who the six eyewitnesses saw running down Salford Street and turning the corner on to Grasslands Road was Lachie," he said.

Coroner Ho was not convinced that he had heard the entire truth about what happened that night and did not rule out the possibility of third-party involvement.

"On the evidence, it is certainly possible that Lachie could have run out to the ponds by himself, entered the water and drowned, notwithstanding the apparent impediments of bare feet, a full nappy, unforgiving surfaces and the late hour," he said.

"Lachie could have entered the water, whether under his own steam or by being placed in it by someone else, at any point in the 340 metres between the top of the south pond and where he was found."

The post-mortem

The pathologist who performed Lachlan's autopsy told the inquest he was reluctant to do the post-mortem because Southland was not set up to autopsy children and he did not routinely perform them on children.

The coroner noted he did not raise his concerns with the duty coroner, instead saying he considered it would be a kindness to his family to have the autopsy done locally and police did not regard the death as suspicious.

The pathologist did not perform a full autopsy but maintained he found nothing suspicious and stood by his findings.

The coroner said the examination and report were "not completed to the standard which would allow me to safely rely on their contents" and he exercised "extreme caution" on relying on anything in the post-mortem report.

The conversation with the duty coroner - which there was no record of - did not absolve the pathologist's responsibility to provide appropriate medical advice, coroner Ho said.

Coroner Ho said the evidence left three possible causes of death - drowning, drowning secondary to head trauma and fatal head trauma - none of which crossed the balance of probabilities threshold so the cause of death was undetermined.

It was plausible that Lachlan could have drowned in the pond but he did not have enough evidence to make an official finding, he said.

While he understood the pathologist was no longer registered to practice medicine in New Zealand he said it was appropriate for the Medical Council to be aware of his findings to make an informed decision if the pathologist sought to practice again.

Next steps for police

Coroner Ho directed experienced police to re-investigate Lachlan's death.

"Had I the power to do so, I would require that any re-investigation be led by an experienced officer from outside Southland District," he said.

"It would be beneficial for a fresh lens to be applied to the investigation and any conflicts of interest minimised. ... it is to be a full and fresh investigation."

Coroner Ho strongly urged anyone who had further information about the events of 29 January 2019 to contact the police.

The inquiry would remain open until he got the report.

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