A man threatened a Wellingborough shopkeeper with a knife before stealing cash.
The armed robbery happened between 9.30 and 9.40pm last Friday evening, April 19, at Great Park Stores, in Great Park Street.
Shortly before the raid, between 8.50pm and 9.30pm, a man was spotted walking past the premises on several occasions.
He then entered the store, threatened the shopkeeper with a knife and demanded cash from the till.
The victim handed over cash and the robber made off on foot along Great Park Street towards Wellingborough town centre.
The man is described as white, aged 20-30, 6ft tall and of medium build. He spoke with a local accent.
He was wearing a dark blue jacket with a grey hooded top underneath, blue tracksuit bottoms and white trainers.
Before entering the store, he wrapped a black scarf across his face.
Witnesses to this incident should phone Northamptonshire Police on 101. Alternatively, phone Crimestoppers anonymously on 0800 555 111.