Police have released CCTV footage after armed robbers entered a Derbyshire Co-op and threatened staff with knives.
Detectives investigating the robbery released moving footage of the crime and details of a potential witness they are trying to trace.
They said: "At around 10pm on Tuesday, August 23, two men entered the Co-op, in Draycott Road, Sawley, holding knives.
"They threatened staff and took cigarettes and money from the till before leaving on some sort of motorbike.
"One wore a grey top with blue stripes down the sleeve and red crash helmet with silver stars. The other wore a blue top and a black cap. His face was covered with a blue scarf."
As part of the investigation, police are trying to trace a man who went into the Tamworth Road Co-Op, in Long Eaton, at around 9.45pm that evening and told staff there were two men acting suspiciously outside.
Detectives added: "He could have witnessed something which may help the inquiry. The man, who was in the company of a woman, is white and he wore a dark blue t-shirt with a round, white logo on the front."
Officers are also hoping that one of the robber' distinctive motorcucle helmet may help trace him.
The helmet has been identified as an RST Cobra Vent in red and silver, with some black detailing in the pattern.
It was worn for the duration of the robbery by one of two men who demanded cash and cigarettes from staff at the Co-op, in Draycott Road, Sawley, and detectives investigating the robbery want to hear from anyone who recognises the helmet or knows someone who owns one.
Witnesses or anyone with information should call DS Scott McDermott on 101, quoting reference 16000248474.
You can also call Crimestoppers on 0800 555 111.