The expert phase of Coroner Alexander Ho’s inquest into the 3-year-old’s death continued in Invercargill yesterday.
In 2019, Lachie was found 1.2km from his Gore home, face up in an oxidation pond. Police quickly concluded the boy had drowned, but later confessed they "missed some steps" in the investigation.
Lachie’s father, Paul Jones, never believed his son drowned and suspected foul play.
Dr Carmen Basu, a paediatrician who had experience in the children’s emergency department at Starship Hospital, gave evidence that Lachie could have walked to the oxidation ponds in bare feet.
"At the age of 3 years 8 months, a child has the physical capacity to walk 1.2km. Some children can even run this distance," the witness said.
Dr Basu said it was unusual for children to drown in shallow water, but water up to Lachie’s neck may have caused him to panic and lose balance.
She said the possible scenarios for Lachie included: something pulled him under the water, he had a medical event, he was held under the water or he had a head injury which caused him a concussion or instant death.
The witness explained Lachie may have been exploring the water, slipped backwards and hit his head and died instantly or drowned.
There are subtle signs of a head injury which the pathologist who completed Lachie’s autopsy may have missed because his head was not internally examined, she said.
"Sometimes the bruising doesn’t look significant but the underlying injury can be."
Dr Basu did not think there were signs of Lachie being neglected and nappy rash and respiratory conditions were common in New Zealand.
She was not concerned that Lachie was still breastfeeding and in nappies.
It was possible for a child Lachie’s age to climb over the fence near the oxidation ponds, she said.
"It’s the same height as most slides in playgrounds," she said.
"Preschoolers are risk takers by nature."
She said statistically, it was most likely Lachie drowned, as accidents were among the most common causes of death in children.
The fact that Lachie walked the distance on his own and was found face-up were unusual aspects of the case, Dr Basu said.
Nick Khan, a Post Haste driver, gave evidence that he did not believe Lachie’s mother, Michelle Officer, was at the Gore depot on January 29, 2019 as she claimed she was.
The witness said in the afternoons he would spend most of his time at the depot and only complete deliveries for less than 20 minutes at a time.
Ms Officer said she was at the depot for 25 minutes from 4.55pm. At 5.20pm she sent a text to her son saying: "at depot, blocked in".
"Nobody can get blocked in in there. It’s a massive open yard," Mr Khan said.
He said it was possible that he was on a delivery while Ms Officer was at the depot, but did not think it was likely because there were packages outside when he arrived back which he thought Ms Officer would have moved if she were there.
Data from package scanners showed multiple packages were scanned at 4.55pm, at two locations that were 3km apart.
Mr Khan said two scanners could not be logged in simultaneously under the same employee code without one being automatically logged out.
Therefore he did not think it was possible Ms Officer was working at one location while Mr Jones scanned packages elsewhere.
The witness thought one explanation could be that the scanner froze and only recorded the packages had been scanned once it was docked at the depot.
Gore District Council’s three waters operations manager, Aaron Green, gave evidence about the depth, makeup and slope of the oxidation pond.
He said sometimes a white foam forms around the edge of the pond.
The inquest will continue today. Lachie’s half-brother, Jonathan Scott, is expected to give evidence.
