Two men have been arrested over the suspicious disappearance of a Colombian national who police fear is dead.
Sergio Cuesta disappeared more than four months ago after he was dropped off by a friend at a Jabiru Drive address in Chelsea Heights, 30km southeast of Melbourne.
The 28-year-old Colombian national had been at a birthday dinner in the Melbourne CBD on the night of September 16, Missing Persons Squad Detective Inspector David Dunstan said.
"He took a call and asked a friend to drive him down to this Chelsea Heights address," Det Dunstan told reporters on Tuesday.
"He didn't indicate why he was going to that address.
"(His friend) drove him there and dropped him off and that was the last time he was seen."
A concerned female friend, who was also at the dinner, alerted authorities after failing to hear from him for five days.
He had not spoken to his family back home in Colombia - something he did often, police said.
A 49-year-old Mount Eliza man and a 48-year-old Cranbourne man were arrested on Tuesday and will be interviewed by police over Mr Cuesta's disappearance.
Police said Mr Cuesta's disappearance was "completely out of character".
The 170cm tall man with a solid build and dark hair was known to police and had been on bail for drug trafficking offences.
"He did travel to Queensland a couple of weeks before his disappearance but we're unsure what his movements are prior to his disappearance," Det Dunstan said.
"Sadly, we do believe at this time that he has met with foul play and is no longer alive."
Mr Cuesta had been living in an apartment on Queens Road on an expired student visa before he vanished.
Investigators have spoken to some of Mr Cuesta's friends in Melbourne, several involved in drug trafficking, but have received varying accounts of the Colombian's final movements.
Det Dunstan on Tuesday appealed to the public, especially those in the Colombian community, for information about Mr Cuesta's current whereabouts or why he went to Chelsea Heights.
"It's every parent's worst nightmare to have their child go missing and the distance between having his parents in Colombia so far away just makes it all that worse," he said.
"We're really seeking some answers to ... bring it back to his mother."
Anyone with any information is urged to contact police or Crime Stoppers.
