Julia DeLuney pictured on CCTV at the BP station in Johnsonville, on her way to her mother's house, at 5.47pm on 24 January 2024. Photo: Supplied
Phone data shows a 37-minute window in which Julia DeLuney's phone was locked and inactive on the night her mother was killed.
She is currently on trial at the High Court in Wellington charged with her 79-year old mother Helen Gregory's murder, which she denies.
Giving evidence, detective constable Mitchell Murdoch walked the jury through Gregory and DeLuney's movements that night, based off CCTV footage and device data from their phones and Gregory's laptop.
DeLuney said she was at her mother's house to book tickets to the ballet. She told police her mother was searching for a shirt she had lost, and went into the attic to look for it.
She said her mother then fell from the attic, causing a wound to the back of her head.
But from early in the investigation, police questioned her account, saying the injuries DeLuney described did not match the extent of the blood which emergency services found at the scene and were not consistent with a fall.
Phone data showed between 9.01pm and 9.38pm DeLuney's phone remained locked and she missed multiple calls and messages from her husband.
The data shows there was also a gap of nearly the same length in activity on Gregory's phone.
Julia DeLuney on CCTV buying a lighter at the Mobil petrol station in Johnsonville, on her way from her mother's to her own home in Paraparaumu, at 9.52pm on 24 January, 2024. Photo: Supplied
DeLuney's phone data showed her flashlight was turned on at 9.39pm, which coincided with CCTV footage of her descending the steps outside her mother's Baroda Street address to the street, captured on a neighbour's security camera.
But phone data also showed Gregory's phone ascended one floor - tracked by the Apple Health app - about 9.35pm. The defence said this showed Gregory did go into the attic that evening.
Crime scene photographs already shown to the jury showed blood around the entrance to the attic.
But Murdoch said the way phones tracked movement between floors was a "relatively inaccurate science".
The defence's case is that Gregory fell from the attic, and her daughter went to fetch help. In that window, the defence said, someone else entered the house and fatally attacked Gregory.
But the Crown says DeLuney attacked her mother, leaving her dead or dying, before staging the scene to look like Gregory had fallen and driving back to Paraparaumu to fetch her husband.
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