A robber who apparently used a pair of underpants to hide his face during a raid is being hunted by police.
The masked man, who was armed with a carving knife, robbed a gas station in England at on Tuesday night.
A CCTV image of the criminal has been released in a bid to help catch him.
Officers said the man grabbed the 36-year-old cashier and held him in a headlock while holding the knife at his back.
The robber then forced him to open the register.
A spokeswoman for Essex Police said: "A cashier was alone in the shop when a man - with his face covered by what is thought to be a pair of white underpants or boxer shorts - walked in, brandished a knife and demanded money."
Detective Sergeant Kevin Cooper said: "This was a nasty incident in which the robber used force and threatened the cashier with a knife.
"The cashier was unharmed but obviously badly shaken."