The latest search to locate missing mother-of-three Samantha Murphy’s body could finally unravel the mystery of what happened to her, according to one expert. 

The 51-year-old was last seen leaving her home on Eureka Street in Ballarat, Victoria, to go for a run in the Canadian State Forest on the morning of February 4.

A month later, Patrick Orren Stephenson, 23, was charged with her murder at Mount Clear on the day she went missing.

He is not speaking to detectives and they have yet to piece together the chain of events following her alleged murder and what has happened to her body.

‘Ms Murphy disappeared seven months ago, which seems like a long time but it’s not really, all things considered, and detectives wouldn’t disclose publicly a lot of what they’re doing,’ criminal psychologist Tim Watson-Munro told Daily Mail Australia.

‘If this happened in Melbourne CBD, for example, there would be a lot more people around – potential witnesses, less places to dispose of evidence.

‘We’re talking about a vast rural area, there’s dense forests and farmlands. It really is like trying to find needle in a haystack.’

But Dr Watson-Munro said the fact that an arrest was made quite quickly – along with the discovery of Ms Murphy’s phone in near-perfect working condition on the bank of a dam in May – showed police had intelligence they were acting on. 

‘That phone was found near a muddy dam and had no degradation and the suspect has been in custody, so that raises the question of whether someone, a third-party, put that phone there,’ he said.

Dozens of police on Wednesday morning converged on an area of bushland where they believe Ms Murphy’s body could be as part of a new targeted search. 

Detectives from the Missing Persons Squad were joined by specialist officers from NSW Police and their federal counterparts.

Victoria Police Missing Persons Unit Detective Inspector Dave Dunstan said up to 45 officers with horses, dogs and motorbikes would scour the area near Grenville, south of Ballarat, as soon as heavy rains eased.

The search areas are in rugged terrain west of Enfield Plantation, which has been previously searched.

‘The danger is there are a lot of mines here as well and that’s one of the reasons we’ve brought out Search and Rescue,’ he said. 

‘There are a lot of unidentified mines … so it’s super dangerous.’

Police are understood to be searching different areas spanning up to a three kilometre radius.

Dr Watson-Munro said the new search, especially in an area that had already been scoured, showed police could be zeroing in on what happened to Ms Murphy.

‘The fact they haven’t located Ms Murphy yet doesn’t mean they’re not moving forward on the case, they could be working on covert intelligence and so on,’ he said.

‘This is shown by the fact they found her phone so long after the event.

‘Of all the dams in the area, police happened to focus in on that on.

‘Phone batteries go flat within a matter of hours, if it was the last ping from that phone then surely police would have found it weeks earlier.’

Dr Watson-Munro also said it was not unusual that a suspect was not talking to police.

‘Without going into specifics about the suspect, who must be presumed innocent until proven otherwise, generally those arrested have a right to maintain silence,’ he said.

‘Most suspects act on legal advice. More often than not, a suspect will maintain the right to silence.’

He also added the Australian Federal Police joining the effort to locate Ms Murphy showed police were determined to uncover what happened to her.

‘Bringing in the AFP clearly shows a strong motivation to find her, to get this solved,’ he said.

‘In terms of the expertise they bring, they would have a broader resource base but also it could be as simple as a fresh perspective to look at the case.’

Grenville is about a 10-minute drive from Buninyong, where Ms Murphy’s phone was found buried in the mud on the edge of an agricultural dam.

Scores of officers set out in soggy conditions on Wednesday to search the area, which shoulders bush, farmland, several timber plantations and the Yarrowee River.

‘Since February, police have regularly undertaken a range of inquiries and small-scale searches as part of the current investigation,’ Victoria Police said in a statement.

‘We are not in a position to supply further specific details of today’s operational activity at this time.’

Ms Murphy’s disappearance led to an outpouring of grief in the Ballarat community and the nation, leading to an influx of volunteers joining the earlier searches.

Police have asked the public not to help on this occasion.

Police in March charged Stephenson with the murder of Ms Murphy. 

He will front court in November, after prosecutors asked for a delay to go through an extensive evidence brief including reams of CCTV footage.

Stephenson is the son of Orren Stephenson, who played 15 AFL games for Geelong and Richmond between 2012 and 2014.

Ms Murphy’s family has been advised of the new search.