A robber held a knife to the throat of a blind woman with two children as she stood in a post office queue and demanded cash from counter staff. The woman instinctively put her hand up which was gashed in the raid at a newsagents in Clayhill Road, Basildon, Essex, on Saturday.
Police said the robber, brandishing a craft knife, then turned his attention to a second woman.
He escaped towards Coddenham Green with several hundred pounds.
'Outrageous' attack
A paramedic was called to treat the injured blind woman.
The robber is described as white, in his early 30s, 6ft tall and had light brown hair.
He was wearing a long sleeved top, beige trousers and trainers.
Det Sgt Colin Norton said: "This was an outrageous incident which left several people in considerable fear.
"The individual concerned is dangerous and must be caught. The knife was a dirty red colour and was covered in tape," he added.