Altona North Embona Taskforce detectives are continuing to investigate a number of armed robberies in Maribyrnong and Braybrook, Victoria Police say.
Investigators have been told a man entered a restaurant on Ashley Street, Braybrook about 8.40pm on 24 November.
The unknown man produced a firearm and made threats to staff members before stealing cash and fleeing on a bicycle.
It is believed the same man attended a service station on Williamsons Road, Maribyrnong about 10.15pm on 27 November.
The man again produced a firearm and made demands for cash to an employee.
He again stole an amount of cash and was seen cycling west on Williamsons Road on a bicycle.
Investigators believe the two incidents are related to armed robberies committed in Hampstead Road, Maribyrnong on 30 September and 17 October 2018.
Detectives have released CCTV vision of a man they believe can assist with their enquiries.
He is perceived as Caucasian in appearance, between 20 and 30 years old, and about 170-180cm tall.
Anyone who recognises the man or has information is urged to contact Crime Stoppers.