One line of inquiry police are looking at is that Vincent Atulia and Andrew Colivas suffered drug overdoses

Vietnamese police are investigating whether drugs were involved in the deaths of two men, including one who had previously been jailed over a bikie-linked shooting.

Vincent Atulia died in mysterious circumstances while holidaying with mates in Vietnam. Picture: Supplied

Vietnamese police are investigating whether two Melbourne men who died suddenly on the weekend suffered overdoses.

Vincent Atulia, 24, and his mate Andrew Colivas, 25, had been holidaying in the South-East Asian country when they died in what have been described as tragic circumstances.

An outpouring of public support has resulted in almost $100,000 being raised to help their families bring the pair home and pay for funerals.

The Herald Sun has confirmed one line of inquiry is that Atulia and Colivas had suffered drug overdoses.

The Department of Foreign Affairs and Trade has said it is helping three other Australians.

DFAT has said it is providing consular assistance to them but is unable to make any further comment because of privacy reasons.

Atulia and Colivas are both from the southeastern suburbs.

In 2020, Atulia was locked up over a bikie-linked shooting incident in Melbourne’s east.

Atulia pleaded guilty to affray over an incident in which a shot was fired into a Ferntree Gully home.

He was among five men, one a Rebel bikie, who travelled in convoy to the property on June 8 of that year.

Atulia had in 2020 pleaded guilty to affray over the incident.

Atulia did 35 days on remand for affray and was handed a one-year community corrections order. Picture: Supplied

They tried to coax outside a man, his sister and another woman, who was the ex-girlfriend of one of the visiting party.

The former boyfriend — not Atulia — then allegedly pulled out a gun and fired it into the home’s upper-storey, leaving a bullet lodged in a closet inside.

Atulia did 35 days on remand for affray and was handed a one-year community corrections order by Magistrate Tara Hartnett, who asked how his time behind bars had been.

“Boring”, he replied.

Magistrates Hartnett said the incident would have been frightening for people in the street.

“Some of you went on this occasion to the house in some sort of misguided loyalty … things unravelled and they unravelled quickly,” she said.

Andrew Colivas was holiday with mates when he died in mysterious circumstances. Picture: Supplied

Court records reveal Atulia had other run-ins with the law in recent years, having faced charges over illegal hauls of abalone, burglary, refusing breath tests, driving an unregistered car, contravening a community correction order and failing to answer bail.

Colivas has previously been charged with affray, operating a water vessel in contravention of a waterway rule, refusing to comply with the direction of an authorised officer and traffic offences.

Families and friends have paid tribute to the two men after announcing they had died in Vietnam.

The families of Mr Atulia and Mr Colivas have set up online fundraisers to bring the men home and help pay for funerals.

GoFundMe pages for both men – who are from the southeastern suburbs – say they had died “tragically” in recent days in Vietnam.

Supporters moved by the tragedy rallied around the pair, donating tens of thousands of dollars for the pair.