An armed robber threatened two men working at a convenience store in Essex and stole hundreds of pounds.
The man, who was wearing a paper mask and had a kitchen knife, went to Premier in West Street in Southend on Friday night.
He threatened staff and demanded money and was given cash from the till.
The man left the store and headed towards Victoria Avenue. He is described as in his early 20s, of skinny build and about 6ft tall.
He possibly had shaven blond hair, but this was obscured by the mask. He was dressed in tracksuit bottoms and a grey hoodie.
Det Sgt Phil Smith said: "I want to hear from anyone with any idea who this man is.
"Do you know someone who has suddenly turned up with a large amount of cash who fits the description?
"The shop workers have been left shaken up by their ordeal and I would urge anyone with information to contact detectives."