A worker at the Maori Women's Refuge was told "Aunty Tania would punch Moko" but did nothing about it, an inquest into the little boy's death was told.
However, the social worker says her original comments to police were either "inaccurately written or understood" and no violence against Moko Rangitoheriri was ever disclosed to her.
The conflicting statements came out during the evidence of Detective Inspector Lew Warner, the first witness at the inquest held by coroner Wallace Bain in the Rotorua District Court.
Moko died after suffering severe beatings by his caregivers. He was nearly 3.
Warner was the officer in charge of the homicide inquiry and said Tania Shailer, Moko's caregiver, called 111 on August 10, 2015, to say the toddler had hurt himself falling from a woodpile.
This innocent explanation did not match Moko's horrific injuries, said Warner, and a criminal investigation began when he died that evening.
Shailer and her partner, David Haerewa, were jailed in June 2016 for 17 years with a minimum non-parole period of nine years after pleading guilty to manslaughter.
They appealed their sentences, saying they were too harsh. But the Court of Appeal rejected the bid and said the pair should count themselves "fortunate" they were not jailed for life.
Operation Corsa, as the inquiry was called, also investigated the volatile relationship between Moko's parents: Nicola Dally-Paki and Karauna Rangitoheriri, also known as Jordan Tawa Rangitoheriri.
Warner said the couple had been together about nine years and Moko had two older siblings, who have permanent name suppression.
The police inquiry also looked into how Moko came to be living with Shailer and Haerewa in Taupo.
Moko's older brother was admitted to hospital with an infection and Child Youth and Family (Cyf) were notified, said Warner. The child protection agency was also told about significant family violence between Dally-Paki and Rangitoheriri.
However, Warner said Cyf did not discuss the "reports of concern" with police.
When Moko's brother was readmitted to Starship Hospital on May 2015, Moko and his sister stayed with various family friends in Auckland.
The following month, a head teacher at a Taupo kindergarten where Shailer's children went made a "report of concern" to a Family Works counsellor.
Although Shailer was a capable parent, the teacher thought she needed "urgent help" for depression and social needs.
Yet just a few days later, Moko and his sister were taken to Taupo to live with Shailer - a friend of Dally-Paki - Haerewa and their four children.
Within four days, Shailer and Dally-Paki sent the following text messages to each other:
SHAILER: "Bro..its ok but uve gt 2 remember I have 4kids n we already live week to week sis..N I no uve gt so much on ur plate at the mo but so do we bro!Huri up gt sht sorts aiight cause kids r missing u!"
DALLY-PAKI: "Alguds bro I understand ur point of view...the following wk I'll cum dwn pik them up will have sumthing sorted fr them by then."
In the following weeks, the pair exchanged more messages about Dally-Paki coming to get her children.
In July, Moko's sister attended a programme at Te Whare Oranga Wairua, which was organised by a social worker, who worked for Maori Women's Refuge.
The course was for children who have witnessed domestic violence.
According to Warner's evidence, Moko's sister told the social worker she and Shailer had been hitting Moko.
"Aunty Tania would punch Moko but she made sure to say that the punches didn't hurt," is how the social worker described her conversation with Moko's sister to police, which was recorded in her statement.
The social worker then asked Shailer about it, according to Warner, but Shailer denied hitting Moko.
The social worker then changed her story to police, said Warner, to say she never spoke to Shailer.
No "report of concern" was filed.
According to media interviews, the social worker now says Moko's sister never said anything about Shailer hitting Moko.
In her brief of evidence to the coroner, the social worker said her statement to police about how "Aunty Tania would punch Moko" was either "inaccurately written or understood".
The social worker said Moko's sister said Shailer hit her - not Moko - when the siblings were fighting.
"She also told me that Aunty Tania would punch her to stop the arguing," said the social worker. "I immediately asked her to demonstrate what she meant by punch and she folded the tips of fingers and pushed my shoulder."
The social worker discussed this with her manager and it was agreed this was a disciplinary measure to protect the sister from Moko.
However, according to a report by Detective Senior Sergeant John Wilson, the social worker's first comments about Shailer hitting Moko were verified by a social worker who witnessed the original conversation with police.
"This retraction is clearly as a result of [the social worker] realising she should have reported what were obviously signs that child abuse was going on in the Shailer/Haewera household," wrote Wilson in a report handed to the inquest.
During this time, text messages from Shailer to her friends reveal she was struggling to cope with Moko and his sister, as well as her four children in the house.
"Morning sis I was having ugly moments these other 2 kids r doing my head in...and my depression is playing up hard out."
In other text messages, Shailer calls Moko a "mother****er" and "c***" for smashing a window.
On July 22, 2015, Dally-Paki texted Shailer to say her other son would be discharged from hospital in three weeks. At that point, she would be able to collect Moko and his sister from Shailer.
The following day, according to medical records obtained by police, a Taupo GP referred Shailer to a psychiatrist.
"This was regarding a borderline personality disorder and related to Tania having self-harm tendencies, mood swings and sleep deprivation."
In the weeks before Moko was killed, Shailer visited the Women's Refuge and spoke to the social worker of concerns about the children returning to Dally-Paki.
The social worker went with Shailer to the Cyf office in Taupo to officially raise these concerns at the end of July.
A few days before Moko was fatally injured, Shailer attended a counselling session with Family Works and disclosed she was looking after the two extra children.
"Tania advised that she was struggling to cope with the behaviour of these children and referred to them as traumatised children," Warner said.
"She further said that Moko would have bruises from banging his head against the wall."
A follow-up appointment was made the next day, because of the counsellor's fears, but Shailer did not turn up.
On the morning of August 10, 2015, Shailer dropped her children off at kindergarten where her behaviour was noted as "out of character" and she smelled of cannabis.
She also told a friend about Moko "running into walls and acting weird and fighting with his sister", as well as falling down the stairs.
The friend said Shailer should have called as she would have taken them to hospital.
That night, at 10pm, Moko was pronounced dead.
Warner is the first of 10 witnesses to give evidence. Others include three Cyf staff members - who have name suppression - and Moko's mother Dally-Paki.
Arama Ngapo-Lipscombe, lawyer representing Dally-Paki, listed 10 individuals and six agencies involved with Moko before his death.
"Would you describe this list as extensive?" she asked Warner.
He replied in a quiet voice: "Yes".