A missing Sydney father may be connected to the same criminal underworld figures as slain drug dealer Jaime Gao and a high roller shot dead outside a McDonald's in Sydney's inner west this year.
Police are investigating potential links between the two deaths and the disappearance of Baker's Delight franchisee Phuoc Minh (Paul) Nguyen, the Sydney Morning Herald reports.
"We believe they may have been associating with the same people and we are exploring the links," a police spokesman said.
Jaime Gao's body was uncovered near Cronulla in a surf board bag. (Supplied)
Former detectives Roger Rogerson and Glen McNamara remain in custody, charged with shooting 20-year-old Mr Gao dead in a storage unit in Sydney's southwest.
It is alleged the pair stuffed his body in a surf board bag before casting it out to sea near Cronulla.
Detectives believe both Mr Gao and Mr Nguyen may have mixed with the same crowd as Peter Tan Hoang, 36, who was gunned down outside the Croydon Park fast food restaurant on September 7.
The Vietnamese refugee turned professional gambler had wagered more than $90m at Australian casinos and was awaiting trial at the time of his death after being arrested carrying $1.5m in alleged proceeds of crime.
Peter Tan Hoang who was gunned down outside the Croydon Park fast food restaurant. (Supplied)
Mr Nguyen has not been seen or heard from since May 1 when he was last seen driving out of the Hilton Sydney hotel on George Street in a brown Renault Latitude rental car.
Police believe he was possibly murdered and are investigating his alleged links to drugs and money laundering syndicates.
The 50-year-old father had spent the day shopping at high-end stores with his sister-in-law.
She has since refused to cooperate with police.
It is believed Mr Nguyen went to a Bankstown massage parlour that night and made his last known phone call at 11.38pm.
A rental car agreement belonging to the father was uncovered from a Liverpool hotel waste bin three days later, after a group of cannabis-smoking men triggered the room's fire alarm.
An empty phone box, the stub of a boarding pass and business cards belonging to Mr Nguyen's associates were also seized by police.
"The group were questioned but we don't know who put it all in the bin," Detective Inspector Sean Heaney said.
"We have strong reason to be concerned that he has met with foul play somehow," he said.
Police are asking people to keep an eye out for Mr Nguyen's rental car with Victorian registration plates ZXH305.
In the lead-up to his suspected death, Mr Nguyen was driving a meat delivery truck for about $2000 a week in the Cabramatta area. It is believed a person connected to the truck had strong links to money laundering and drug rings.
Mr Nguyen's brother Tony said the businessman acted strangely in the lead-up to his disappearance.
"He handed my sister-in-law's passport back to her that night and said, 'I'm meeting up with someone and it could be complicated.' "