Mobile phones belonging to accused killer Borce Ristevski and his alleged victim, wife Karen, were both deactivated on the day of her disappearance, a Melbourne court has been told.
The 54-year-old claims Karen, a fashion boutique owner, left the couple's Avondale Heights home in June 2016 after an argument to clear her mind, and never returned.
Ms Ristevski's remains were discovered wedged between logs by two horticulturists working at Macedon Regional Park eight months after she vanished.
The 47-year-old's cause of death has not been determined.
Detectives claim Borce murdered his wife at home and drove her black Mercedes-Benz roadster to dump the body, killing the signal on his mobile phone along the way.
They claim he lied about where he was on the day of Karen's disappearance and made inconsistent statements.
Optus technical specialist Oleg Prypoten told Melbourne Magistrates Court on Monday that both the Ristevskis' phones were detected on June 29, 2016 - the day Karen went missing - before they were deactivated.
He said Optus could detect phones if they were on and even if they'd been left idle.
However, he said the couples' phones had been deactivated either because they had been turned off, switched to airplane mode, or run out of battery.
Court documents show Borce's phone was unable to make or receive calls between 11.09am and 12.51pm.
Karen's phone last pinged to a cell tower in Gisborne, near the Macedon Regional Park, at 11.40am.
But Optus couldn't pinpoint where the phones were last used as they could have pinged off a number of different stations within the area.
Mr Prypoten said Optus could detect phones within a 35km-radius in rural areas
Earlier on Monday, police failed in their bid to prevent Mr Prypoten's evidence being reported by media, arguing it could reveal too much detail about their investigation methodologies.
Magistrate Suzanne Cameron refused the request, stating that what occurs during police investigations is regularly discussed in open court.
The court has previously been told the Ristevskis were in financial dire straits and would sometimes argue about money and business in the lead up to Karen's disappearance.
Prosecutors have compiled a 22,000-page evidence brief, including CCTV footage of Karen's Mercedes, phone recordings and telecommunications data.
The committal hearing, which is expected to conclude this week, will determine whether Borce will stand trial over his wife's death.