Frankston Embona Taskforce detectives are appealing for witnesses following an armed robbery at a milk bar in Seaford last month.
Investigators have been told a man armed with a knife entered the milk bar on Armstrongs Road just before 4pm on Wednesday 15 May.
It is alleged he entered the milk bar several times without purchasing anything before making demands for cash from the attendant.
The female attendant handed over a small amount of cash and the bandit fled the scene.
He was last seen running east on Armstrongs Road.
No one was injured during the incident.
The offender is described as being Caucasian in appearance, aged 16 to 21-years-old with a slim build and dark hair.
He was wearing a black hooded jumper and dark sunglasses.
Detectives have released an image of a man they believe may be able to assist with their investigation.