Three men stole money and cigarettes from a shop in Bury.
The offenders walked inside the Coop store on Walmersley Road and smashed a glass panel in the front door.
A shop assistant and customer saw the men and ran to the back office at around 9.50pm on November 30.
The trio took the till, cigarettes and a set of keys before they drove off in a black car.
The staff member and customer were not hurt.
One is described as being white, 5ft 9in tall, of slim build and spoke with a local accent. He wore a black hooded top with the hood pulled tight around the face, black pants and trainers.
The second man is described as being white, 5ft 9in tall and of slim build. He wore a grey hooded top with the hood pulled tight around his face, blue denim jeans and trainers.
The third man is described as wearing a white jacket.
Detective Constable Lindsey Worrall from Bury CID said: “We believe the men may have driven off in a black Vauxhall Astra as the car was spotted leaving the scene at speed. I would ask anyone who was in the area at the time and may have witnessed the offence or the car driving off, to contact us.”
Anyone with information should phone police on 0161 856 8248 or the independent charity Crimestoppers, anonymously, on 0800 555 111.