The jury in a High Court trial has been shown a photo of a double-murder accused standing on the graves of the victims.
Pakeeza Yusuf was found buried under Takapuna overbridge with her 3-year-old daughter Juwairiyah "Jojo" Kalim in October 2014.
The Crown alleges the pair were murdered by Kamal Gyanendra Reddy, 42, at the end of 2006 or start of 2007.
After a six-month undercover police operation, which began in April 2014, the defendant sat down with an officer and was repeatedly asked to disclose any significant secrets he may have.
The two interviews, which were covertly filmed on the same day, were played for the jury at the end of last week at the High Court in Auckland.
Prompted by a series of questions in the second sit-down, Reddy told an undercover officer he strangled Ms Yusuf with the cord of an electric iron while she was in bed.
"She's gone and then after, I go for the daughter," he said.
"So I just got rid of her ... and take her body and dump it where the new bridge was making on the North Shore."
He then unwittingly took an officer to the spot, and after some deliberation posed for a photo where he believed the grave was.
"Just go and stand where you reckon the middle of the hole will be. Just stay there," the undercover cop told him as he took the picture.
When Reddy was asked if he was sure that was the location he replied: "100 per cent".
He earlier told officers he had smothered Jojo with a pillow and afterwards disposed of items including the iron and pillow case.
The accused said he and his then partner had been arguing that night and she had told him to leave.
"She was sleeping and she said: 'go home from my life, go home here. I don't want to see you anymore'," he said.
Thinking he was speaking to a friend rather than a covert operative, Reddy told the officer he had put the corpses in his car and driven to the Bombay Hills, south of Auckland, to dispose of them.
When he could not find an appropriate spot, he allegedly opted to bury them in Takapuna under a motorway bridge that was under construction.
"I put, dig it up, big dig, took me almost whole night to dig it up because no cameras, no security there," he said.
When asked how he knew Ms Yusuf was dead, Reddy said her arms and legs had gone "tight".
The court will hear over the next few days how an undercover officer gained the defendant's trust through a series of "simulated criminal scenarios" before he made the admissions.
Soon after, he also took officers to the exact burial spot, where they found the bodies the following day.
But at the trial's opening, defence lawyer Jonathan Krebs warned the jury to be skeptical of the so-called confession.
"I say to you from the outset: it's false, it's a cobbled-together story."
He said his client was effectively groomed by undercover officers to the point where there was "immense pressure" on the 42-year-old to make admissions.
"What if a person didn't commit the crime but knew enough about the crime to give a plausible narrative?" he said.
The trial continues.