Lincolnshire Police are investigating a knifepoint robbery at a food store in Boston.
The offender entered the store on Vauxhall Road at around 8.20pm on Monday, June 5, stealing approximately £500 from the till.
The shop assistant was shocked but unhurt by the incident.
A police spokesperson said: “The suspect is described as a tall slim male, who was wearing a blue top with a black scarf across his face and either a black cap or hood covering top of head.
“DC Goffe in Boston CID would like to hear from you if you have any information that could assist the enquiry.”
Anyone with information should call the non-emergency 101 number, quoting incident 91 of June 6.
Alternatively, contact the independent charity Crimestoppers anonymously on 0800 555 111.