Police killer Dezi Freeman suspected of sexually exploiting two children

Police killer Dezi Freeman is suspected of sexually exploiting two children before gunning down two officers and spending months on the run, the ABC can reveal.

Freeman, a so-called sovereign citizen, opened fire on constables Neal Thompson and Vadim de Waart-Hottart in August last year, before disappearing into the bush at Porepunkah, in the state's north-east.

In addition to those murders, Freeman also shot and wounded a third officer and tried to open fire on another.

The police officers, who had surrounded the makeshift bus Freeman used as a home, had a warrant to seize his devices as they investigated allegations of historical child sex offences, which are believed to include allegations of sexual exposure.

The ABC previously revealed hundreds of files of child abuse material were discovered on Freeman's devices after the raids.

Until now, it was believed there was one alleged victim.

But two law enforcement sources have told the ABC that Freeman is now suspected of sexually abusing two children.

The exact circumstances of the alleged offending remains unknown.

Details about Freeman's alleged offending were aired in the Victorian coroners court earlier this year, ahead of inquests into the officers' murders and Freeman's death during a police shootout in March.

Counsel assisting the coroner Lindsay Spence told the court Freeman was being investigated over an alleged sexual assault of a child under the age of 16 and an alleged attempt to involve a child in the production of abuse material.

The ABC understands detectives had previously been in contact with one alleged victim.

Freeman spent 216 days on the run before he was tracked to a rural property at Thologolong, more than 150 kilometres north-east of Porepunkah.

Police still searching for those who helped Freeman

On March 30, officers from Victoria Police's elite Special Operations Group negotiated with Freeman for three hours while he was holed up in a converted shipping container.

The alleged paedophile emerged from his hideout wrapped in a blanket and cradling a service pistol stolen from the body of one of the slain officers.

He pointed the gun towards police and was shot multiple times.

His death ended Australia's largest-ever tactical police operation, which brought in more than 500 personnel state, interstate and federal police, as well as police from New Zealand.

A $1 million reward for information leading to Freeman's arrest prompted more than 2,000 tip-offs from the public.

It is not known whether the reward was ever claimed.

Investigators from Taskforce Summit, the Victoria Police operation set up to find Freeman, have since raided and questioned several people in Victoria's High Country and regional NSW about their potential connections to Freeman, and whether they aided him as he evaded capture.

Among those raided were Kay and Bruce Reid, the parents of AFL premiership players Ben and Sam Reid, who told the ABC about their long friendship with Freeman.

In June, Ms Reid revealed their Buckland home in Victoria's north-east had been searched by police, who seized their phones.

Ms Reid has previously rejected any suggestion that the couple had ever aided Freeman.

"We had nothing to do with it… as if we're going to do that, as if we would've assisted, spare me," Ms Reid said.

Several other raids were also carried out in Victoria and NSW.

Investigators now believe Freeman travelled across the border into NSW while he was on the run and received assistance from several people.

The ABC can reveal police believe those arrested and released since Freeman died are loosely linked through shared sovereign citizen beliefs.

Police have been using their powers of arrest to seize electronic devices, predominantly phones, as they try to uncover any network that supported him, the ABC understands.

No charges have been laid.

The inquests into Freeman's and the officers' deaths are due to begin in March next year.