The biggest manhunt in Victoria’s history has returned to the spotlight, with police saying there were strong beliefs their fugitive, Desmond 'Dezi' Freeman, had died in the Mount Buffalo National Park.

Coordinators of the search for Freeman along with more than 100 specialist and volunteer resources set upon a fresh five-day search on Monday on the back of what they say is the most important piece of public information they have received to date.

Detective Inspector Adam Tilley of Taskforce Summit said while police were keeping an open mind to three main possibilities five months after the 56-year-old’s disappearance, one was becoming clearer than others.

“We do believe strongly that he is in this area, deceased,” he said

“We have done extensive searching of the caves, the mines, the huts, the rivers, we are comfortable that we don't believe he is here alive.

Police remain open to the possibility of Freeman being alive in the bush alone or being harboured.

Freeman has not been seen since fleeing his Rayner Track property in Porepunkah after allegedly shooting and killing Detective Leading Senior Constable Neal Thompson and Senior Constable Vadim de-Waart-Hottart and seriously injuring a third officer on the morning of 26 August.

A team of 10 officers were executing a search warrant as part of an investigation by the Wangaratta Sexual Offences and Child Abuse Investigation Team about 10:30am that day.

The fresh search will take place in an adjoining area of a five-day search conducted in December last year on the western side of the Buckland River among heavy, thick bushland.

Police say both searches are based on intelligence obtained in relation to a gunshot heard about 12:29pm on the day of the fatal incident, in the vicinity of Barrett Lane and Rayner Track.

A range of firearms tests were conducted in November to pinpoint the gunshot’s exact location.

The December search covered around 0.886sq km, with this week’s search expected to cover 1.3sq km, or the size of 52 MCG ovals.

Det Insp Tilley said heat exposure and bushfire risks had delayed the taskforce’s search efforts since December.

“This is the largest manhunt we have seen in Victoria and tactically it is the largest operation that’s occurred in Australia,” Det Insp Tilley said.

“It’s not going on a bush walk in terrain like this; it is extremely challenging… at parts you don't even know where you're stepping, you have to be extremely careful.”

Detectives have investigated over 2000 pieces of intelligence, including information received from the public.

Det Insp Tilley said every piece of information provided by the public had been thoroughly investigated by the taskforce and he thanked the local community for their ongoing support.

“This matter will be resolved with the public's assistance,” he said.

“Everyone who is involved in this investigation would like to have questions answered and some form of clarity that we can provide an update to the families of Vadim and Neal, to the colleagues affected by this and to the local community.

“I can speak on behalf of every detective that's on this task force we want answers, we want resolution.”

Taskforce Summit was established in October to coordinate the search for Freeman and investigators continue to have a daily presence within the Great Alpine area.

Det Insp Tilley said the taskforce led by detectives from Crime Command have been making ongoing enquiries within the community.

The Homicide Squad continues to lead the investigation into the deaths of Led Sen Const Thompson and Sen Const de Waart-Hottart.

While the Mount Buffalo National Park remains open to visitors, Det Insp Tilley urged the community to be mindful of the police presence within the park during their visits and of the risk of seeing Freeman himself.

“The ongoing risk is we don’t have intelligence or information that supports any one theory more than the other,” he said.

“We say if Desmond Freeman is still out there, he is armed and dangerous, and if you are looking after him, just be mindful that he can still cause harm to others in the community.”

Victoria Police will continue to maintain an enhanced presence in the local Porepunkah and Mount Buffalo National Park areas and remain resolute in bringing the investigation to a conclusion.

Anyone who sees Freeman should phone triple zero (000) immediately and not approach him.

A reward of up to $1 million remains for information leading to Freeman’s arrest.

Anyone with any information on Freeman’s location, or anything the community notices at the Mount Buffalo National Park should be reported to Crime Stoppers Victoria via 1800 333 000 or www.crimestoppersvic.com.au