Brimbank Embona Taskforce detectives are investigating after a gunman robbed a pharmacy in Deer Park on Sunday 21 May, Victoria Police say.
A man entered the Station Road business and produced a handgun, demanding cash from a staff member about 7pm.
An amount of cash was handed over and the offender fled on foot.
He was last seen running along Station Road towards Kororoit Creek.
No one was injured during the incident.
The man is perceived to be Caucasian in appearance, aged in his early to mid-30s, about 183cm tall, with a medium build, short beard.
He was wearing a thick dark-coloured jacket and holding a black garbage bag.
Investigators have released some images of a man that may be able to assist with their enquiries.
Anyone with any information is urged to contact Crime Stoppers.