An anti-communist group led by former South Vietnam military commanders terrorised refugees who did not back their cause in Australia, according to declassified FBI documents.
The documents show that the anti-communist National United Front for the Liberation of Vietnam ambushed a picnic of refugees in Canberra, and that the violent attack was not an isolated incident.
The Front has been linked to murders and serious beatings in the US, but it is unlikely the group was as cold-blooded in Australia, according to law enforcement and intelligence sources, and prominent members of Australia's Vietnamese community. 
In   November, US website ProPublica and investigative documentary series Frontline reported that the Front was suspected of murdering five Vietnamese journalists working in the US between 1981 and 1990, and included details from declassified FBI documents.
The allegations caused fresh angst about the presence of anti-communist groups within Vietnamese refugee communities in Australia and North America.
It can now be revealed that the FBI documents contained new information about violence involving Front members in Australia.
Australian Vietnamese, including those involved in a group that evolved from the Front, welcomed an investigation into any anti-communism-related violence that may have occurred.
The Front was led by former South Vietnamese Navy officer Hoang Co Minh, who wanted to reclaim Vietnam from communist forces by galvanising refugees scattered across the globe after the fall of Saigon in 1975.
The FBI documents contain an excerpt from anti-communist Vietnamese newspaper Chuong Saigon that describes the attack on a gathering at Black Mountain Peninsula, which juts into Lake Burley Griffin, on   September 10, 1983.
The excerpt claims the Canberra meeting was ambushed as it comprised "pro-communist henchmen".
Vietnamese community members across Australia recall intimidation and standover tactics being deployed by the Front in order to raise funds and support among refugees after the fall of Saigon.
It is possible individuals within the Front lashed out without the expressed backing of the movement at those who slighted them, according to law enforcement sources and community members.
The murder of an Adelaide businessman bears some similarities to attacks by Front members in the US, and remains unsolved, but it is unclear if links to anti-communism were ever investigated.
Vo Van Ngo was last seen in   December 1985, when he boarded a tram in Richmond.
His body was found in a car on the Hume Highway near Wangaratta. He had been stabbed and bashed, and police at the time said the killing did not appear gang-related.
A Victoria Police spokeswoman was unable to confirm whether the Front was investigated as part of the probe into Mr Vo's murder.
Vietnamese Community in Australia president Phong Nguyen said that while there were rumours that the Front was linked to bashings in Melbourne, and many refugees felt intimidated, he did not know of any confirmed incidents of violence.
Emeritus Professor Carl Thayer, from the University of NSW, has written extensively about anti-communist Vietnamese groups.
He said there were two other violent acts involving the Vietnamese population in Canberra in the 1980s that might have also been linked to the Front: shots fired at the Vietnamese embassy in O'Malley, and the bashing of Vietnamese students staying at the Canberra College of Advanced Education.
Hoang, the Front leader, was killed while trying to cross into Vietnam from Laos with other guerillas in 1987.
While that was the end of the push to take back the country, the Viet Tan, the modern incarnation of the Front that has denounced violence and describes itself as pro-democracy rather than anti-communist, continued to lobby for a democratic Vietnam, and retains a strong presence in Australia.