Police have admitted failings in an emergency call made the day before a toddler was found dead, saying they let the girl and her family down.
Two-year-old Nevaeh Ager was found dead in tidal mud flats in Maketū, in western Bay of Plenty, in March last year. Her father, Aaron Izett, was found guilty of her death this year.
The day before, her great-grandmother Niki Sturgess had called 111 about Izett and Nevaeh's wellbeing in his care.
Sturgess said Izett had attacked her and her husband, telling them Izett was "off his brain".
She was told police couldn't intervene because she didn't have custody.
After more reports the next day, police found Nevaeh's body in a nearby estuary, weighed down by rocks.
Today an Independent Police Conduct Authority (IPCA) report found police had failed in their responsibilities regarding the call.
The call-taker hadn't coded the event correctly, gave out wrong advice and didn't record details which could have impacted the police response. Meanwhile, the first dispatcher didn't check the database for information about Izett, while the second did but didn't copy that information into the 111 event.
IPCA chair Colin Doherty says it's an "extremely sad case".
"While police processes were found wanting, due to uncertainty about the exact timing of Nevaeh's death it is not possible to say whether police would have prevented her being harmed if they had gone to check on her shortly after Mrs Sturgess' call."
Assistant Commissioner Tusha Penny says police "could and should have done more" in the situation.
"We let Nevaeh and her family down," Penny says.
"We will never know whether we could have prevented this tragic outcome, and for this we are deeply sorry."
She says police apologised to Nevaeh's family in person yesterday.
In response to the incident, police say they've held "professional conversations" with the involved staff and provided further risk assessment training.
Izett is due to be sentenced in February.