Detectives are trying to piece together the final movements of a man after his body was found in a lake in Sydney's southwest.
The man is yet to be formally identified but is believed to be a 48-year-old from Ambarvale, NSW Police said in a statement on Wednesday.
He was reported missing to police just before 6pm on Saturday when he failed to return home from work and his body was found in Lake Gillawarna at Georges Hall about 4pm on Monday.
Police said the man caught a taxi from Queen Street in Campbelltown to a boat ramp on Rabaul Road in Georges Hall - which is one kilometre from where his body was found - in the early hours of Saturday morning.
CCTV footage shows the man exited the taxi outside a petrol station near the boat ramp and a grey sedan was later seen arriving at a nearby car park with two occupants walking in the direction of the man.
A second vehicle - a dark coloured SUV - was later seen arriving and exiting the car park.
Detectives are calling on the community to help to piece together the man's final movements and to help identify the two people who exited the grey sedan.
"We are very keen to speak to the occupants of the vehicles who pulled into the Georges Hall boat ramp car park and may have seen the man in the early hours of Saturday morning," Superintendent Murray Reynolds said in a statement.
"We are awaiting the results of a post-mortem examination so, at this stage, the man's death is being treated as suspicious until we can rule that out."