Coroner Alexander Ho's inquest into the 3-year-old's death in 2019 continued at the Invercargill courthouse on Tuesday morning.
Police quickly concluded the toddler had drowned after being found face up in a council sewage pond in Gore.
Jade Vigers, a friend of Lachie's half-brothers Jonathan and Cameron Scott, gave evidence today via video link from Australia.
Mr Vigers said in 2019 that he had known the family for more than 10 years.
Max Simpkins, counsel for Lachie's father Paul Jones, asked the witness if he was the kind of person who would stop what he was doing and help Jonathan Scott if he needed a favour.
“Yes, absolutely,” the witness replied.
“Johnny needed help that day because his brother had tragically died and I suggest you already knew Lachie had died,” Mr Simpkins said.
“You can imagine anything you want, but that doesn't make it true,” Vigers said.
Mr Simpkins asked the witness if he helped Jonathan Scott dispose of Lachie's body that evening.
“You should be ashamed of yourself if you say that, it's disgusting,” the witness responded.
Mr Simpkins asked if the witness could tell the court “the real story” about what happened to the toddler.
“Lachie went on adventures and got into trouble, just like little kids do,” he said.
He said he first became aware of Lachie's disappearance that evening when Kimberley Marshall, a neighbor who was searching, asked if he had seen a little blond boy.
Mr Vigers asked if they were looking for Lachie.
The witness said that although he was good friends with the family, he only went to the house when Lachie's father Paul Jones was not there.
“I would only go there if Paul wasn't there because he was really scary to be around,” the witness said.
Mr Vigers denied conspiring with others to portray a poor image of Mr Jones.
Earlier today, the court heard from more neighbors, including Tanya Ogilvy, who went looking for Lachie with fellow resident Deborah Thurston.
Ms Ogilvy said she heard a “commotion outside” so left her home to investigate.
She said she heard Mrs Thurston and Lachie's mother Michelle Officer shouting the boy's name.
The witness said she joined Mrs. Thurston and they walked to the gate near the oxidation ponds where they saw a dog barking.
Debby said [Lachie] wouldn't have gone this way because he didn't like dogs,” Ms Ogilvy said.
Several other witnesses were questioned about animals they saw at the pond, but Ms Ogilvy is the only one who mentioned a dog.
Ms Thurston did not make a statement about a dog but said she did not think the little boy would have entered the area with the ponds because the fences were too high.
The investigation will continue this afternoon.