A former Sergeant who was involved in the initial investigation following the death of Lachie Jones told a coronial inquest the police at the time were under-resourced and inexperienced.
The 3-year-old was found dead in a sewage pond in Gore after going missing in 2019.
Police twice concluded he accidentally drowned.
Lachie's father, Paul Jones, does not accept the police conclusion his son drowned.
Former Sergeant Hua Tamariki on Friday told a coronial inquest he believed the Eastern Southland policing area was poorly resourced and lacked experience at the time.
" .... we got into a practice - [it] wasn't the best practice - we had to pull together to do a lot of things where ordinarily a police structure... would make it clear who did what," he said.
Tamariki said he was tasked to lead the investigation's inquiry phase to identify witnesses, ensure they were spoken to and understand how Lachie had gone missing and ended up in the pond.
"I did not have any CIB (Criminal Investigation Branch) or investigation training, so I completed the inquiries to the best of my abilities."
During cross-examination, it was put to Tamariki it was the view of staff on the night this was an accidental drowning.
It was also put to Tamariki that, in the early hours of the morning, there was still a long list of things police didn't know.
Yet, after observing the scene and viewing Lachie's body, another member of the police decided no scene guard was needed.
Tamariki agreed the list of things police did not know was longer than the list of things they did know.
The inquest continues next week.
