What phone ‘pings’ can tell us in the Samantha Murphy case

Police are using phone data to work out who was in the area at the time missing Ballarat mum Samantha Murphy vanished. This is how the crucial investigative technique could help crack the case.

Phone pings could be used to identify possible persons of interest or suspects as the search for missing Ballarat mum stretches on.

And experts say the “mega task” of sifting through data from phone towers in the sprawling bushland of the Woowookarung Regional Park where the mother-of-three was last seen could take weeks.

The Herald Sun revealed on Monday investigators were set to trawl mobile metadata captured near Ms Murphy’s last known location after she vanished on the morning of February 4.

People whose phones “pinged” from mobile towers covering the zone Ms Murphy was in the hours after she set off for her run at 7am, are expected to be looked at.

Veteran former homicide detective Charlie Bezzina said the data may help police zone in on suspects.

“I would guess they’re looking at somebody and looking for a particular phone of a person of interest or suspect,” he said.

“They might have been in an area and they’re able to say, well OK you were there. That’s also how you can negate any alibis.

“They may have identified someone in a car or a witness has identified somebody. It just goes to support any allegations that the police will eventually make against certain people.”

Mr Bezzina said it was a “mega task” for police to undertake and would take investigators weeks to sift through the data.

“You might have three or four towers within a five or a 10km radius,” he said.

“They might end up with 1000 or 2000 phones in that area at the time people are passing through, and then they go through the laborious task of identifying them all and doing background checks or possibly interviewing them.

“It’s a very significant labour intensive exercise for Victoria Police to undertake. So they are really going to the full extremes.”

The former detective said it was a “shame” telecommunications companies charge Victoria Police thousands of dollars to hand over data for investigations.

“It is a significant cost to Victoria Police to do, I’m talking thousands upon thousands of dollars to get a tower dump,” he said.

“We’re getting into an age now that a lot of investigations really rely heavily on these types of devices and relevant data.”

Associate Professor Mark Gregory from RMIT University’s school of engineering said it may be harder to get extensive phone data in the regional area due to a lack of coverage.

“The word ping just means the phone was identified in the logs of a particular phone tower. It doesn’t mean that the phone did anything, other than the mobile tower made a note that that phone was within range on a particular day, at a particular time,” he said.

“The next step would be to look at whether the phone tried to utilise the tower, for apps or phone calls.

“The only way to avoid a tower is to make sure the phone is powered off, and even more so, with the battery moved.”

Associate Prof Gregory said for the telecommunication companies, the data would be automated.

“Police will go backwards and forwards with the telcos to get information. To get contact details, phone numbers, account numbers, to see if there’s businesses involved,” he said.

“(Police) will try and look at who was in the area at the time of interest, where were they, what were they doing. They can also see if other devices such as wearables or a car were connected to the network.”

Associate Prof Gregory said police, for example, could look for similar mobile data as seen on the day another Ballarat resident, Sissy Austin, was brutally attacked while out jogging in the nearby Lal Lal State Forest.

“What they might do is the same exercise for that day a year ago and see if there’s any correlation. Are there any anomalous devices in the area? Devices that only appeared on that day and this day?” he said.

But he said phone data is not a “guaranteed way to solve a crime”.

“It’s a tool. It is one approach that might help provide a lead. But it is the small things that help crack cases,” he said.

“It may be that the person, all persons involved, if there was foul play, might have turned any device off or left them at home.”

Phone pings could be used to identify possible persons of interest or suspects as the search for missing Ballarat mum stretches on.

The telecommunications expert said phone data has been a key component of other high-profile missing persons cases in recent years, including the rescue of four-year-old Cleo Smith in Western Australia in 2021.

“In that case it was successful. They found an anomalous reading on one of the towers and because it was in the middle of the night, it was a clear red flag,” he said.

Phone data was also crucial in the case of Ballarat woman Kobie Parfitt, who disappeared in April, 2020. Analysis of a suspect’s phone data in that case led investigators to the mine shaft where her body was dumped after her murder.

Detectives on the Murphy case are already dealing with more than 700 information reports and working their way through 12,000 hours of CCTV.

Phone data led to a fresh recent search of an area at Mount Clear, 6km from Ms Murphy’s Eureka St home, after it pinpointed a more precise location where her phone had been that morning.

Phone data led to a fresh recent search of an area at Mount Clear, 6km from Ms Murphy’s Eureka St home. Picture: Brendan Beckett

There were initial reports Ms Murphy’s phone pinged off the Buninyong tower at 5pm on the day she was doing a 14km jogging course. Those reports remain unconfirmed but, if true, would add another strange layer to the case because it came 10 hours after she left for her run.

Detective Superintendent Mark Hatt said recently it was unlikely investigators would find Ms Murphy alive.

He said that one or more people could have been involved in her removal from the area and detectives were looking at “absolutely everything and every possible scenario.”

A Victoria Police spokesperson said police are “actively engaged” with a number of external agencies and telecommunications companies in an effort to get as much information as possible to assist the current search.

“Given this investigation is active and ongoing, we are not in a position to provide further detail about these processes at this time,” they said.