UPDATE 1.07PM: A teenager who was getting change to use a car wash said he witnessed the stabbing death of a young man outside a Cobram service station.

Reid Wilson, 18, told the Border Mail he was at the door of the Caltex service station on the corner of Station Street and the Murray Valley Highway when a fight broke out between two groups of young men about 10.30pm last night at the petrol bowsers. 

"They started grabbing each other's shirts and as they were doing that, one of them just pulled out a knife," Mr Wilson said.

Mr Wilson said he saw one of the men get stabbed in his stomach.

"It was crazy and everyone was yelling," he said

UPDATE 1PM: Detectives are interviewing a 27-year-old man over a fatal fight in Cobram after he showed up at a Melbourne police station.

The incident at the Cobram service station on Thursday night left a 20-year-old man dead.

Detective Senior Sergeant Shane O'Connell from the homicide squad said the fight in the border town started as a verbal altercation between a number of people before escalating into physical violence.

"As a result, one person is now deceased," he told Fairfax Radio.

He said two men left the scene in a silver Commodore before police could speak with them.

Police say one of those men then reported to police at 10am on Friday at Broadmeadows police station in Melbourne, about 230km south of Cobram.

The man, from Cobram, is being interviewed about the fight, but no charges have been laid at this time.

The second man has not yet been found.

A post-mortem examination is yet to be carried out to confirm a cause of death.

UPDATE 11.145AM: A man is dead after what police claim was an altercation outside a service station on Victoria’s northern border.

The Age reports officers arrived at an area outside a Caltex service station on Murray Valley Highway and Station Street, Cobram, about 10.30pm on Thursday.

Ambulance Victoria spokesman John Mullen said paramedics arrived at the service station about 10.30pm, and, despite their efforts to resuscitate the 20-year-old man, he was pronounced dead at the scene.

Homicide Squad detectives were called to the scene, and the investigation is continuing.

According to 3AW Radio, initial reports indicate the man was stabbed to death during a fight,  but the coroner is yet to determine the cause of death.

Detective Senior Sergeant Shane O’Connell from the Homicide Squad said police are looking for two men who left the station in a silver Commodore before police arrived.

Senior Sergeant O’Connell said what started in a verbal confrontation on Thursday night, escalated into a fight.

‘‘There is some indication from witnesses that we spoken to that there was a verbal exchange beforehand,’’ he said. 

‘‘Whether that extends to them being known to each other is in the early stages of our investigation, and we’re not quite sure of that at this stage.’’

‘‘There were quite a number of people present. Most of the people that were in the general vicinity remained until police arrived, but there were two gentlemen who left before (police arrived).

‘‘We’re very keen to talk to those people,’’ Senior Sergeant O’Connell told 3AW Breakfast.

Anyone with information is asked to phone Crime Stoppers on 1800 333 000, or visit www.crimestoppers.com.au.

EARLIER: THE Homicide Squad is investigating the death of a man after a fight outside a Cobram service station on Thursday night.

Police were called to the service station on Murray Valley Highway and Station Street around 10.30pm.

A 20-year-old man died at the scene.

A Victoria Police spokesman said the cause of his death had not been determined.

Anyone who may have information is urged to call Crime Stoppers on 1800 333 000 or visit www.crimestoppers.com.au.