"But while he looks comical, he has pulled a gun out of the sling and shown it to the teller, as a mother and her son are standing right next to him," Avondale Police detective senior sergeant Marcia Murray said.
The man made the teller empty the tills before fleeing. Police attended the scene but the man could not be located or identified.
Investigations continued but four months later, the same premises was robbed again.
At 2.20pm on April 12, a man entered and approached the front counter with a bag and demanded money from the teller.
"This time round the man has his face covered with a bandana, his hoodie is up and he's wearing sunglasses.
"He's holding a double-barrelled sawn-off shotgun which can be seen by the teller," Murray said.
Again the man takes the money and flees down a driveway next to the building.
Both incidents lasted less than a minute, police said. "Our CIB team has been looking into these for some time and we have exhausted a number of lines of enquiry.
"We believe they are linked and we strongly believe that the person/s responsible will have told someone.
"This is a person who will have suddenly had a lot of money that he didn't have before, and family members or friends might have wondered why."
Anyone with information is asked to contact the Avondale CIB on 09 213 8448.
Information can also be given anonymously to the organisation Crimestoppers on 0800 555 111.
