The incident took place around 4.50pm on Thursday, February 7 at a shop on Albion Road.
Officers have released CCTV images of a man they believe can help with their ongoing inquiries.
A male entered the premises, presented a weapon and made a demand for money before leaving the store.
The man detectives are eager to speak to is white, aged 20 to 25, slim, with brown hair shaved at the sides.
He is pictured here wearing a grey thigh-length jacket with a fur trim, possibly Stone Island, black trousers, black trainers with white soles and black gloves.
Detective Constable Jo Robertson of Gayfield CID said: “An investigation is underway and we’re now appealing for the public’s help as part of this.
“Anyone who may have information regarding this incident or who may recognise this man is urged to report this to either us or Crimestoppers anonymously as soon as possible.”
Those with information can call Police Scotland on 101, quoting incident number 2889 of February 7, or report this anonymously to the charity Crimestoppers on 0800 555 111.
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