By Adam Cooper
The mobile phones belonging to Borce Ristevski and his wife Karen were detected on the day she went missing, but a telecommunications expert has been unable to pinpoint exactly where the phones were that day or why they were deactivated.
Prosecutors allege Mr Ristevski murdered his wife of 27 years on June 29, 2016 and drove her body in her car from their home in Avondale Heights to Mount Macedon Regional Park. Her body was found in the park eight months later, between two logs.
Borce and Karen Ristevski.
Mr Ristevski, 54, is charged with murder and on Monday entered the second and final week of a hearing at Melbourne Magistrates Court that will determine whether he stands trial. He will plead not guilty if committed to appear before a jury.
The court heard last week the Ristevskis’ phones pinged telecommunications towers that morning, before the phones were deactivated.
But on Monday the complexities of tracking mobile phones were outlined by electronics engineer Oleg Prypoten, a senior technical expert with Optus.
He said Optus could track phones if they were on, even if they were sitting idle and not being used to make or receive calls or text messages or access the internet.
Optus could track phones within a 20-kilometre radius of a base station in an urban area and a 35-kilometre radius within a rural area, Mr Prypoten said, but that didn’t mean the phone was being detected by the nearest base station or tower.
But the phones couldn’t be detected if they were deactivated, he said, by being turned off, switched to airplane mode or if the battery was flat.
Prosecutors allege Mr Ristevski deactivated his and his wife’s phones to avoid detection as he drove along the Calder Freeway to the park. The Calder runs north-west of Avondale Heights.
However, Mr Prypoten confirmed one of the phones was at one point detected by a base station located between Truganina and Lara, which are south-west of the Ristevskis' home.
Victoria Police had wanted Mr Prypoten’s evidence and witness statements not to be reported so as not to divulge the ways investigators use telecommunications data.
Media organisations opposed the application and on Monday magistrate Suzanne Cameron ruled not to impose a suppression order. That means media can report Mr Prypoten’s evidence.
Ms Cameron said Mr Prypoten’s evidence should be held to the same scrutiny as that of other experts, and that there was nothing unique in his evidence or that wasn’t known outside court. There should be a presumption in favour of open justice, she ruled.
Prosecutors allege Mr Ristevski either killed or incapacitated his wife between 8.58am and 10.43am on the day she went missing, during an argument over the financial difficulties faced by their clothing business, Bella Bleu.
The hearing continues.