Moorabbin Crime Investigation Unit detectives are investigating after an armed robbery at a donut shop in Carnegie last week.
Investigators have been told a man entered the store on Koornang Road around 9.15pm.
The man ordered a donut and when staff asked for payment, he produced a syringe, demanded money and threatened to stab the staff member.
The man fled the store with cash and the donut and no one was injured during the incident.
The man is described as Caucasian in appearance, 175cm tall with a medium build
He was wearing blue tee shirt, grey track pants, a black leather jacket, white runners, a black beanie and a black facemask.
Police have released CCTV and images of a male they believe can assist them with their enquiries.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or at www.crimestoppersvic.com.au.
